Search Documents

The methods employed in dressing 'the tin ore up to the required percentage of purity depend mainly on the type of ore crushed.These may be briefly divided into two distinct classes-viz., q, free: milling ore and a complex milling ore. In the former the ore is practically free from the common metallic sulphides, such as pyrites, mispickel, blende, galena, etc., and 1!' clean concentrate of 70 per cent metallic tin can be directly obtained in one continuous act of concentration; in the latter, however, in order to get a good extraction, it is only advisable to primarily concentrate up to 30 to 40 per cent. tin oxide, the rest being the sulphides of the metals. This concentrate is then roasted, re-ground, and re-concentrated up to 70 per cent. metallic tin on a separate set of tables.In the complex milling ore the tin is intermixed very closely with the sulphides, so that it becomes necessary to collect all the mineral present in order to obtain clean tailings. Stamp mills are the most popular machines for the primary crushing in the district, but whether they are invariably the best for the purpose is rather an open question. No doubt for some of the very tough chloritic ores they are the most efficient, but for a brittle quartzose ore, such as the free milling proposition usually is, the writer thinks Oornish rolls would well hold their own, especially when the tin occurs coarse, as is so often the case with this class of ore. Of course, the great drawback to stamps is the excessive quantity of tin slimed and slime tin is one of the problems of tin-dressing-while rolls give...

Jan 1, 1907

By P J. Ellen

The selection of the ore haulage system is a key decision made in the development of an underground mine. The haulage system is one of the components that define a mineÆs ability to respond to changes in mining inventory and market conditions. The complexity of this decision for Telfer Deeps was affected by the realisation during the feasibility process that the true scale of the potential underground mineralisation at Telfer was still to be quantified. This paper provides an overview of the process used in the Telfer Project Feasibility Study to select an ore haulage system for Telfer Deeps. The purpose is to highlight the value of impartially approaching tasks of this type with a robust process. The process should be able to respond to issues identified as the task progresses towards the objective of finding the best solution for an ore haulage system for the mine. For Telfer Deeps, this process resulted in the selection of a haulage system built around a shaft. The systems considered during the feasibility are discussed and the components of the haulage system constructed for Telfer Deeps are described.

Jan 1, 2005

The occurrence of metallic minerals in Australia to the time of the proclamation of South Australia as a Colony in 1836 was unknown. It is, therefore, perhaps, surprising that British settlers arriving in the Coromandel included among their number a German scientist Johannes Menge who had been appointed by the South Australian Company to the post of Mine and Quarry Agent and Geologist on 1 July 1836. His instructions were to `explore the natural productions of the Colony above and below ground and to superintend the working of quarries of stone and slate, the boring for water, metal, lead, coal and other mines at a salary of ú150 per annum for one year and for as much longer as the Company require your services not however exceeding five years'. In the event, he was to have little influence on those matter.

Jan 1, 1993

By Fourney W. L, Weaver T. A

A large number of single borehole crater-forming shots were analyzed in terms of correlating the crater parameters with explosive weight. The objective was to determine a scaling rule for which the explosive weights varies over many orders of magnitude and covers many different geologic materials. Included in the data base are type and weight of the explosive, geologic medium and degree of saturation, charge depth-of-burial, crater dimensions, and crater rim (lip) measurements. An alternative scheme to the usual plot of scaled depth-of-burial versus scaled volume removed was desired. The proposed technique uses a plot of the logarithm of the explosive weight, Y, versus the logarithm of the slant length, R', calculated from the known depth-of-burial of the explosive and the measured crater radius. A plot of Log Y in kilotons versus Log R' in meters from all the crater tests in this data base resulted in a straight line with a of slope 0.31 and showed good correlation between the variables Log Y and Log R'. Since the crater data includes many geologic materials, different explosives (including nuclear tests), and large differences in charge weight, the straight line fit suggests that the type and strength of the geologic materials play a subordinate role to explosive energy in crater formation.\

Jan 1, 1990

By C Fearon

This paper discusses the implementation of an underground rail haulage system during a major expansion of the Olympic Dam mine in 1998. The factors affecting the selection of rail haulage are discussed and details are provided on the rail system, which is designed to transport more than 10.5 million tonnes per annum (Mtpa). The reliability of the system during commissioning is discussed, including the decision to manufacture a ædummyÆ locomotive in order to keep the system operational. Finally, reliability improvements made both during and after commissioning are discussed with comments provided on the effectiveness of the system as it operates today.

Jan 1, 2005

By S Hughes

The smelting of concentrates and secondary materials has been subject to increasing challenges in recent years due to declining grades of feed materials, increasing impurity levels and ever more stringent environmental regulations. In addition there has been a growing focus on maximising the efficiency of energy usage and recovery of values. New opportunities have been created with rising metals prices and improved systems for the collection of secondary materials, giving rise to a need for more flexible process solutions.This paper focuses on a number of specific cases where a process solution has been developed using the Outotec« Ausmelt Process to meet particular feed material challenges and overcome limitations inherent when employing traditional pyrometallurgical processes.The first case involves the development and commercial implementation of a smelting process to recover values from zinc smelting residues typically deposited into dams as a waste product. The second case describes the application of the Ausmelt process for the smelting and converting of secondary copper feed materials, including e-waste. These materials contain a wide range of metals and plastics and need to be processed appropriately to maximise the recovery of values whilst avoiding environmental problems. The third case study covers the smelting of nickel concentrates containing elevated magnesia levels as well as nickel bearing catalysts with high alumina content, neither of which can be readily processed when employing traditional pyrometallurgical technologies. CITATION:Hughes, S, 2013. Pyrometallurgical process solutions for complex raw materials, in Proceedings MetPlant 2013 , pp 519-530 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

By Sennitt C. M, Hartley J. S

The Twin Hills Gold Deposit is an example of a preserved, high level, epithermal system, with mineralisation introduced contemporaneous with deposition. The deposit is hosted within sediments of the Late Devonian to Early Carboniferous Saint Anns Formation, of Cycle 1 Drummond Basin stratigraphy, situated in central Queensland. Prior to epithermal activity in the Twin Hills region, a lacustrine fan delta depositional environment existed, together with minor tuffaceous activity. An and palaeo climate, with occasional periods of torrential rainfall, together with a basin with faulted margins, allowed alluvial fan prograda- tion. Cyclical repetitions of the fan indicate repeated faulting and seismic activity took place during deposition. Significant gold mineralisation was first intersected at Twin Hills by Metana Minerals NL in 1988, after drill testing a "blind" target outlined by geological mapping and bedrock geochemistry.

Jan 1, 1991

By Dobos K

The Clermont Goldfield, from which about 300,000 oz of bullion have been extracted, was one of the major gold producers in Queensland. This paper is derived from a systematic study of the mineralogy, geochemistry, and stable isotope geochemistry of the deposit, based on detailed field work and logging of 57 reverse-circulation percussion drilling holes at the Black Ridge Gold Deposit (Fig 1), aimed at addressing the long debated question of gold-ore genesis at Clermont, i.e., whether it is of fossil placer or hydrothermal origin.Detailed petrologic and mineralogical studies indicate the hydrothermal alteration at Black Ridge is dominated by extensive siderite (+rhodochrosite-ankerite) veinlets and stockworks, which are concentrated along the deformed unconformity between the Anakie Metamorphics and basal conglomerates of the early Permian Blair Athol Coal Measures. Siderite alteration is also moderately developed in all other rock units represented at Black Ridge, including the Tertiary basalt. Weak to moderate phyllosilicate alteration is common throughout the deposit, including chlorite-sericite along the shear zone of the unconformity, and sericite-clay in the conglomerates. A sulphide-oxides zonation also has occurred, including pyrite below the unconformity, (pyrite)-chalcopyrite-marcasite-(hematite) along the deformed unconformity, and marcasite (hematite, pyrite) in the conglomerates.

Jan 1, 1990

By Readett D. J

Soluble salts can be removed from Bowmans lignite by water and acid leaching. The success of the removal of water soluble or acid exchangeable impurities is directly associated with the efficiency of dewatering these slurries. The filtration characteristics of a slurry at its natural pH (4.0) were poor, with a filter cake moisture of 65%. Acid treatment of the slurry at pH2 caused the filter cake moisture content to drop to 61 %. Various oils, oily surfactants and a flocculant were tested to determine the conditions for minimum filter cake moisture. A series of pilot scale filtration tests were conducted on flocculant dosed slurries with and without washing on a horizontal test unit. Moisture contents of 54% were obtained in laboratory testing using high additions of oily surfactant. For the pilot scale test work, moisture levels close to 60% were obtained with low flocculant additions, similar to results obtained in laboratory studies. Removal of soluble salts could be correlated directly to the final moisture content of the filter cake. This process of leaching followed by filtration resulted in the removal of approximately 75% (more than 80% with washing on the cloth) of the sodium chloride originally present in the lignite.

Jan 1, 1989

Tholeiitic metabasalts comprise at least five geochemically distinct mafic volcanic associations of Late Palaeozoic age within the Gympie Province, southeast Queensland. Geochemical features indicate that parental magmas of the various metavolcanic suites were generated in contrasting tectonic regimes, although each of the suites shows some affinities with eruptives from convergent plate margin settings.Basalts from the Highbury Volcanics of the Gympie Group are island arc tholeiites (IAT) formed during an immature stage of eruptive activity in an intra-oceanic arc. They are unique among the analysed metabasites in possessing high Zr/Nb (Zr/Nb - 30) and very high Ba/Nb, and as well as low Ti/V, Ti/Zr and Ti/Y. These features are explicable solely in terms of contributions from a depleted, convecting upper mantle source, and large ion lithophile element (LILE) enriched fluids ascending from subducted oceanic crust.

Jan 1, 1990

Gold mineralisation at the Kerimenge-Lemenge prospects is a classical example of myltiple, overprinting events, associated with intrusive-related hydrothermal systems. Repeated emplacement of high level dacitic porphyry bodies (Edie Porphyry; 2.4 - 3.8 Ma) was accompanied by a phreatomagmatic eruption which formed a diatreme-maar complex. Later hydrothermal fluids utilised permeable fault zones and diatreme contacts. Mineralisation took place during two main events. Stage I consists of early quartz - illite/sericite - carbonate phase with associated pyrite-arsenopyrite mineralisation. This phase is zoned from quartz - sericite-pyrite/arsenopyrite in the south at depth, to dominantly manganocarbonate - illitic clay - arsenopyrite- pyrite_s significant base metals in the north and at shallow levels. The majority of known gold (18.1 Mt @ 2.0 g/t Au) at Kerimenge is associated with Stage I activity. The gold occurs primary within the lattice of the sulphides and is metallurgically refractory. Fluid inclusion studies indicate early boiling and progressive cooling and dilution of hydrothermal fluids during the evolution of the Stage I event. Near paleosurface condensation of gases, which evolved off the boiling system at depth, produced abundant low pH bicarbonate fluids. During the waning phases of Stage I activity, these bicarbonate condensate fluids descended down permeable structures and formed banded manganocarbonate veins. High grade non-refractory gold mineralisation during Stage II event is restricted to favourable structures at relatively shallow levels and in the northern regions of the prospect area. Gold in this event exhibits a distinctive Au - Ag - Te -Cu geochemical signature, and is associated with hessite - tennantite - chalcopyrite mineralisation within quartz veining. Alteration and fluid inclusion studies indicate that this style of mineralisation is a result of the quenching of pulses of hot, late magmatic mineralised fluids by the cold condensate waters.

Jan 1, 1997

In mineral asset valuation the use of any valuation method requires the input of competent and independent technical professionals. A resource valuation must be as transparent as possible to allow others to assess the validity of their underlying assumptions. Materiality is a dominant factor in all valuations and a valuer should set out the basis for the subjective decisions made in this regard. Any valuation methodology must comply with the requirements of the law, practice notes and guidelines issued by the various relevant authorities and professional bodies. The valuation methodology chosen to value a mineral asset depends upon the amount of data available on that asset and the reliance that can be placed upon those data. Mineral assets generally fall into one of three broad categories, depending upon their state of development, ie whether they are at the exploration, development or operating stage. Naturally there are transition phases. Hence, there are ""Grass Roots"" Exploration Areas and Advanced Exploration Prospects; Pre-Development Projects and Developing Mines; and Operating Mines. The features of each of these mineral asset status categories are described, mainly in terms of the confidence in the contained identified Resources/ Reserves. The various subjective methodologies available for the valuation of ""Grass Roots"" Exploration Areas and Advanced Exploration Prospects -are specifically reviewed. The pitfalls in adopting a ""recipe"" approach are noted. It is the author's view that the Expected Value Method (based on the probability adjustment of the output of a Discounted Cash Flow/ Net Present Value model) has little application in the valuation of exploration mineral assets, so it is only briefly addressed. The methodologies reviewed are listed below. ò Multiple of Exploration Expenditure Method (expenditure based). ò Joint Venture Terms Method (expenditure based). ò Geoscience Rating Methods (eg Kilburn - area based). ò Comparable Market Value Method (real estate based). ò Rules of Thumb (eg $/Resource or production unit; % of in situ value). Some recent Prospectuses are used to provide examples of their misinterpretation and misapplication.

Jan 1, 1994

By D La Rosa, A Jankovi, A Dance, W Valery

This paper presents the methodology for optimising blasting and comminution processes in terms of fragmentation developed by Metso Minerals Process Technology Asia-Pacific and South America (MMPT). The methodology is called process integration and optimisation (PIO) and involves a number of steps: benchmarking, rock characterisation, measurements, modelling/simulation of blasting and comminution processes and where required, material tracking. The measurements collected while at site are combined with rock characterisation and definition of ore domains to model the complete process chain. These data are used to develop site-specific models of blast fragmentation, crushing, grinding and flotation. This allows customised blast patterns to be developed that optimise both crushing and grinding performance. For each domain, blast designs are recommended to generate the optimal fragmentation size for downstream processes. The objective is to minimise the overall cost for the entire process and the changes often have a positive impact on the mining operation. Process constraints such as wall stability, ore dilution, muck pile characteristics, size of mining equipment, size and installed power of crushing and milling equipment and other process bottlenecks are considered in the blast designs. This methodology has allowed many operations around the world to significantly increase their production: generating typically five to 20 per cent higher concentrator throughput. A number of case studies will be discussed in this paper to describe the structured approach taken and demonstrate the benefits that are achievable. This paper will focus on the role of blasting in the optimisation of the entire mine to mill process chain and discuss elements of the PIO methodology: rock characterisation, fragmentation modelling and measurement, the relationship between fragmentation and mill throughput and material tracking.

Jan 1, 2007

Comalco Limited has recently completed construction of a $50 million kaolin plant at the site of its bauxite mining and industrial minerals operation at Weipa. The plant will produce 100,000 tonnes per annum of coating grade kaolin for the paper industry. Comalco produced the first coating kaolin from the deposit in 1979 on a trial basis. Since then a variety of quality coating grades with specific particle size distributions and brightness values have been prepared. Extensive drilling and bulk sampling of the deposit over eight years has shown that the ore body is large and of a high grade suitable for the production of premium quality coating kaolins. The processing plant technology was developed by Comalco in association with the European kaolin and equipment producer Amberger Kaolinwerke GmbH (AKW). The Weipa kaolin plant is the first of this size to be built in the Pacific Basin region and it will offer the region's paper-coating mills a stable and reliable source of high-quality kaolin, shipped from an established bulk loading port. The paper provides an overview of the development of the kaolin investment the nature of the production process and details the

Jan 1, 1986

The price of oil and other minerals may not make the costly business of offshore exploration seem -attractive at present. There is little doubt that the future search for the strategic resources will tend towards deeper waters particularly on the continental slope margins. In addition with the realisation that active tectonic environments (eg the Makassar Straits) cannot be excluded as potential hydrocarbon sources there is an increasing demand by the explorationists for deep water survey capability. Such deep water research has until recently been restricted to a few specialised academic institutions ;however with the anticipated extra, demand from other institutions, companies, and government agencies, Marconi Underwater Systems Limited (MUSL)and the Institute of Oceanographic Sciences in the UK have come together to allow MUSL to provide the deep water mapping system GLORIA on a commercial basis -for the first time. The GLORIA package comprises a deep water(more than 400m) side scan sonar system which, by operating at a frequency around 6.4 kHz can insonify swathes on the seafloor up to 60 km wide. In addition, single channel seismic, 3.5 kHz high resolution profiles, precision echo sounding, magnetic and gravimetric data all combine to provide as complete a regional interpretation as possible. The GLORIA system combines surveying at a reconnaissance level, covering as it does up to 20,000 sq.km per day, with a very high reliability, so that even in- economically unfavourable times, it can-still be considered as an invaluable and cost effective primary exploration tool. Analysis of the GLORIA data enables the identification of areas of particular interest requiring more detailed study by the more costly multi-channel seismics at a later date.

Jan 1, 1987

By Li YQ, Yoon RH

The photoresponse of natural mineral pyrite and galena electrodes has been studied in aqueous solutions on freshly fractured surfaces (some fractured in situ) using moderate overvoltages. When fractured in situ, the electrode potential of both minerals instantly drops several tenths of a volt. Pyrite exhibits a spontaneous anodic photocurrent at fracture, which indicates upward band bending (depletion layer) on the n-type electrodes. The negative surface charge responsible for the depletion layer is believed to arise from a surface state that is intrinsic to pyrite surfaces, possibly modified by hydroxide ion adsorption. The flat band potential, Vty, of pyrite is at approximately -1.0 V (SCE) at pH 9.2 but to reach V(b, pyrite has to be cathodically decomposed. In contrast, galena assumes the flat band potential at fracture. Subsequent polarisation of galena at potentials positive of Vth produces an anodic photocurrent (upward band bending) and polarisation negative of Vro a cathodic photocurrent. Most of the galena electrodes studied were degenerate n-type and at potentials negative of Vtb, no cathodic photocurrents are observed, indicating the bands cannot be bent downward, consistent with the Fermi level at the surface merging with the conduction band edge near Vn,. Several were close to intrinsic, with the photocurrent changing sign near Vn,.

Jan 1, 1993

By A Kuras

Segmental tunnel linings are becoming more common in Australia. One current project employing a segmental lining is the City West Cable Tunnel (CWCT) in Sydney. The project has been commissioned by Energy Australia and is currently being constructed by Thiess Pty Ltd. The project includes 1.6 km of tunnel boring machine (TBM) driven, segmentally lined tunnel. The majority of the CWCT will be excavated through Hawkesbury Sandstone. The tunnel is required to carry a 132 kV electrical circuit under SydneyÆs central business district (CBD), between Haymarket and Energy AustraliaÆs City North Substation on Sussex Street. The segmental lining has been designed as a 3.2 m internal diameter, 200 mm thick universal ring with six trapezoidal segments. The design and detailing of this segmental lining presents some noteworthy challenges, including exposure to saline groundwater, and the exclusive use of steel fibres for flexural and tensile concrete reinforcement. This paper describes some of the key elements of the segmental lining design. These include:the case for choosing segmental linings over other forms of tunnel construction;the major design checks required of a segmental lining including ground loading, hydrostatic loading, joint bearing, joint rotation, ram loading and the early strength lifting case;the benefits of using steel fibres over conventional steel reinforcement;the design approach used for steel fibre reinforced concrete;the application of 3D computer modelling in the design;the provision for components including connector dowels and gaskets;the design for passive fire resistance; andthe design for durability of steel fibre reinforced concrete in a saline environment. Segmental lining design requires the application of specialist design approaches. Input is required by the construction team, as the methods of demoulding, handling, transportation and installation impact on the lining design. As the segmental lining is functioning as immediate ground support and also a permanent lining, high standards of manufacture and construction quality control are required to ensure that the 100-year design life is met. The requirement for a watertight tunnel means that detailing and installation of the EPDM gaskets is of importance.

Jan 1, 2008

By I J. Holland

Located in North West Queensland, XstrataÆs Mount Isa Copper Operations (MICO) is one of the largest underground mines in Australia with annual production exceeding six million tonnes of ore with average copper grades of three per cent. As at 30 June 2006, the Ore Reserve inventory totalled 87 Mt, with annual diamond drilling planned at >40 000 m in order to convert existing resources and test and define exploration targets. The role of the geology department within MICO is to collect, interpret and communicate relevant geological information to ensure the optimal extraction of ore. Routine underground inspections across multiple ore sources are undertaken and the information derived is then distributed to a range of professionals, operational personnel and management. The information is a æreal-timeÆ geological view for the stakeholders. Ongoing data collection and interpretation has developed a strong geological input to all mine planning processes within MICO. This has created strong synergies between mine planning professionals and a throughput benefit has been seen all the way to the concentrator. The MICO geological framework also provides avenues for a geological focus away from short-term production requirements, and as a result significant orebody scale observations and patterns have been realised that have led to an increase in the accuracy of geological and resource models. This has provided practical benefits for short-term scheduling and production, whilst enabling the realisation of long-term benefits that have a strong potential to increase the volume and value of the MICO resource. This paper will discuss the various mine geology contributions at MICO and illustrate some examples where mine geological input from graduate level has added significant value to the MICO business.

Jan 1, 2007

By H M. A Ilyas, M Yahyaei, S Amari, M Darestani

Tailings are generally deposited on or near to the mine sites, occupying the site area, and being an economic burden for mining companies. Tailings can cause several environmental impacts, such as leaking toxic substances and contaminating underground water, emitting greenhouse gases, and damaging natural bodies and wildlife. Geopolymerisation of mine waste effectively transforms mine waste into more valuable, environmentally friendly products. Geopolymers are inorganic aluminosilicate materials that are widely applied in the construction industry (Araya, Kraslawski and Cisternas, 2020). The high performance and the low-CO2 emission of geopolymers make this type of material potentially more desirable than ordinary cement, given that manufacturing one ton of traditional cement generates approximately 0.8 tons of CO2. This process is seen as a promising method for repurposing tailings and reducing the environmental impact of mining waste. However, the environmental impact of geopolymer production is not sufficiently comprehended (Mazzinghy et al, 2022). Moreover, geopolymerisation of mine waste can offer several economic benefits, including reduced waste management costs (Amari et al, 2019; He et al, 2022), reduced raw material costs, and potentially lower production costs. However, there are several challenges that need to be addressed to ensure the economic feasibility of the process. This study aims to demonstrate the potential environmental impacts of geopolymer concrete produced using mine wastes and industrial by-products such as blast furnace slag (BFS). For this, a comparative cradle-to-gate life cycle assessment (LCA) methodology was conducted on different geopolymer mix designs, and the greenhouse gas (GHG) emissions results were compared to the ordinary cement. LCA can be used to evaluate the environmental impact of geopolymerisation of mine wastes in various ways. One important impact category is GHG gas emissions, which contribute to climate change and is the focus of this study. Another aim of this study is to evaluate the economic feasibility of the geopolymerisation of mine wastes via economic analysis (EA) to identify the key economic factors and trade-offs associated with repurposing mine wastes through geopolymerisation.

Aug 2, 2023

By R Farnf, M Pegden, S Hosein, T White

A number of theoretical papers have been published outlining the use of electronic detonators to limit peak particle vibrations levels, but few empirical studies have been undertaken and even fewer examples have been published of the use of such technology in the aggregates industry. This paper gives a summary of the research work carried out at two limestone quarries in the North of England, where a series of blasts were used to compare and contrast the use of electronic and non-electric detonators. The majority of blasts were carried out using the same burden, spacing and decked charge weight loadings. A methodology was established that could be used to reduce the peak particle velocities (PPVs) at two or more specific locations by using single-hole blast vibration signatures in conjunction with specific electronic detonator timing intervals. The initial study concluded that this was only possible if single-hole signature blasts were periodically recorded to establish the shape of the correct vibration envelopes as properties were approached. These wave envelopes could then be used as the basis for choosing the specific electronic detonator timing intervals to give the lowest PPV for the properties or locations concerned. This methodology was then used in the second study to access a large volume of aggregates adjacent to a working railway tunnel. The financial benefit for the company was to convert these additional tonnages of rock from being a resource to an exploitable reserve. The project involved careful blast design and the instrumentation of a number of boreholes to enable the results of blast monitoring exercises to be compared with predicted PPV results. The iterative process involved the vibration results being uploaded into æBlast LogÆ (an expert blasting database system developed by the Blasting and Environmental Research Group at the University of Leeds) and analysed to produce predictions ready for the next blast.

Jan 1, 2007