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By V Ser, R Crosbie

To date, Anglo American Research Laboratories (AARL) has carried out several projects, based on the techniques developed in AMIRA International LimitedÆs (the mineral industries research association) AMIRA P9 project, to develop models for several Anglo Base Metals flotation plants. Further detailed analysis of the data which was generated has realised additional benefits: the various hydrodynamic measurements were useful in comparing cell operating parameters to literature sources, while the laboratory batch tests give an indication of plant recovery potential. A detailed cell by cell mass balance, which is a critical feature of the modelling process, is in its own right a valuable diagnostic tool. Several examples of how this can be used to highlight potential improvement areas in the plants are presented. The added understanding gained from sampling each cell is clear and this is shown to more than compensate for any necessary modifications needed to allow sampling to take place. The model fitting process generates an ore floatability distribution, which is used in the JK SimFloat simulation package to assess the effect of possible changes to each of the circuits. An example of an actual circuit change as a result of this approach is presented. The current limitations of and the potential improvements to the modelling process are also briefly discussed. Future models will be extended to include enhanced size and mineralogical information where the basic models suggest this has potential to improve understanding.

Jan 1, 2005

By B J. Andrew, M R. Daley

Mount Isa Copper Mines is a world-class mining operation producing approximately six million tonnes of ore per annum. With over 50 years of mining history and over 76 million tonnes of underground resource remaining there are many challenges facing the mine technical team today and into the future. The mine consists of nine distinct areas: the Hangingwall Lens, Footwall Lens, 1100, 1900, N1100, N1900, 3000, 3500 and N3500 orebodies. Each of these areas have different characteristics, requiring varying methods of mine design and ground control for safe and efficient orebody extraction. Each of the areas operate with an independent sequence whilst interacting with the entire underground operation. Within the first five years after graduating mining engineers tend to orient their careers in either a technical or operations direction. Engineers working towards a specialised technical career will often be working as mine planning engineers, whilst others more focused in the operations stream occupy roles such as operations or project engineers. At this stage of a mining engineerÆs career they are not yet categorised into one stream or another, but career decisions made now can generally focus their ultimate career path in one direction or the other. Due to the size of the Mount Isa operations there are many opportunities for engineers pursuing both career path and plenty of room for growth forthose as yet unsure.

Jan 1, 2005

By J Charbucinski

Commonwealth Scientific and Industrial Research Organisation (CSIRO), Exploration and Mining, has developed nuclear spectrometric techniques for borehole logging. The paper reviews the latest developments of this technology for the metalliferous mining industries. The SIROLOG logging system developed by CSIRO Exploration and Mining has been commercialised and is available to the mining industry.

Jan 1, 2000

THE nature of the ore deposit of the Broken Hill line of lode is such that it can be broadly divided into two the calcitic and siliceous ore bodies. The principal minerals occurring in these ores are: Galena, sphalerite, pyrite, arsenopyrite, chalcopyrite, pyrrhotite, calcite, rhodonite, garnets, feldspar, fluospar, quartz.Whilst these minerals persist in both classes of ore, the following typical analyses of Broken Hill South Limited ore bodies will give some indication of the disposition with regard to each:

Jan 1, 1928

Brief descriptions of several types of unit pulverizeI' are given and the functioning of the components that crush, carry, dry and classify the coal is considered. A distinction is drawn between pulverizers which crush particle beds and those .operating by free-crushing. The overall performance of pulverijlers is considered in terms of correlations between mill variables, coal grindability, abrasiveness, moisture and particle size. Brief discussioiJ. of the influence of pulverized fuel quality on boiler operation and of pulverizing costs concludes the paper.INTRODUCTIONModern coal pulverizers function as carriers of materials and as crushers, as dryers and as size classification machines and, thus, the unit pulverizer comprises. several components that normally function as separate apparatus. The controls of the unit pulverizer must have sufficient flexibility to accommodate rapid variations of boiler load or coal quality. Further, the machine must be robust, yet easy to maintain preferably at annual intervals-so that maintenance costs are small (for coal is a relatively cheap material). Usually, the full load of a modern pulverized-fuel fired boiler can be raised with one pulverizer off-line. All coals, from anthracites to brown coal, may be prepared as pulverized fuel (hereafter P.F.) .Each pulverizer of a direct-fired boiler has, broadly, to supply the burners with coal powdered so that about 80 per cent passes a 200 B.S. sieve and only a small proportion, less than about 10 per cent, remains on the 100 B.S. sieve. The classification processes must prevent any appreciable proportion of coarse particles in the P.F. and yet not return excessive proportions of "finished" fines. The quality of the P.F. should not vary greatly with output rates which may be anywhere between the maximum rate and one quarter ofthe maximum. The suspension of P.F. in the primary air...

Jan 1, 1957

Continuous pH and Pulp Potential Measurements During Complex Sulfide Ore Flotation

Sep 13, 2010

By C A. Fleming

Gold extraction is largely driven by mineralogical factors, which often cause gold losses to various tailings. Mineralogical factors affecting gold recovery include grain size and shape, surface coating or rimming on gold particles, the presence of cyanide or oxygen-consuming minerals or preg-robbers, the presence of slow-dissolving gold minerals and the refractory nature of submicroscopic gold. Among these factors, locking of fine gold particles in sulfide, silicate and other minerals, either as visible, fine-grained gold inclusions and/or as invisible submicroscopic gold, is by far the most common factor leading to poor gold recovery in gold ore processing. This paper discusses the mineralogical characterisation of gold lost in tailings and its metallurgical implications. The techniques used in characterising the un-recovered gold are also briefly introduced.

Jan 1, 2007

Mineralisation was identified at Gladstone Hill as far back as the late 1870s-early 1880s, shortly after the initial discovery of mineralisation at what is now the Martha Mine. Indeed, early recovery problems associated with the Martha mineralisation led to the preferred development of ore bodies within what is now the Union Hill Joint Venture tenement; ore bodies such as Silverton, Amaranth, and Union to name a few. Gladstone Hill forms the basis of the Union Hill Joint Venture, a 50:50 joint venture managed by Au-Ag Resources Ltd (a fully owned subsidiary of Otter Gold Mines Ltd), and Welcome Gold Mines Ltd (a fully owned subsidiary of the Normandy Group). The joint venture participants also operate the adjacent Martha Mine. Mineralisation of Gladstone Hill, as with mineralisation at the adjacent Martha Mine, has been interpreted as a low sulphidation epithermal Ag-Au system hosted within hydrothermally altered andesites of the lower Coromandel Group. Drilling in recent years has successfully identified extensive mineralisation associated with a number of vein sets throughout the tenement including the Gladstone Vein set, the Moonlight Lode and more recently along a north-easterly trend towards the historic Favona workings. A wide range of vein styles is apparent, ranging in character from thin stock works to broader lode-style banded chalcedonic to cherty quartz and have been interpreted as representing multiple phases of emplacement. At shallower levels mineralisation is often hosted by vein clasts within vent breccias. Visible gold is rare, with mineralisation generally associated with very fine-grained pyrite, arsenopyrite and minor electrum. Percentage levels of combined sphalerite-galena-(+/- chalcopyrite) have been intersected at depth however these have been gold poor to date. The potential for the Gladstone Hill area remains to be clearly defined as drilling to date has yet to close off mineralisation both along strike and down dip. If further drilling is successful, the joint venture partners believe Gladstone Hill could contribute significantly to the economic future of current operations.

Jan 1, 2000

It has been thought in the past that New Zealand had ample coal reserves, able to provide fossil fuel supplies well into the future. Such is not the case and every effort must be made to achieve the highest possible extraction rate in all new coal mining ventures. While the relative cost and availability of completion or fuels has been largely responsible for the slow growth of coal production in the past, a world shortage of fuels has given coal a new importance and required better utilisation of coal reserves. New mining ventures in thick-seam coal deposits cannot be planned and designed without geotechnical investigations designed to provide information required by the mining engineer and analyst. Finite element analysis of mine workings may provide essential information on the optimisation of mining techniques and the design of underground support and roadway shapes.

Jan 1, 1976

Copper ores are widespread through the Lachlan Geosyncline in New South Wales, but the size of the orebodies is generally small. The largest deposits occur in the Cobar district where an iron-rich copper ore type has been developed in Silurian sediments. Similar de- . posits to the south in the Nymagee-Mt. Hope-Melrose districts are related to quartz feldspar porphyries of probable Upper Silurian age. Deposits to the east in the Tottenham-Girilambone districts are less complex mineralogically and are possibly related to an ultra-basic source.Copper mineralization in the Highlands further to the east is often developed in Ordovician andesite or MiddleUpper Silurian acid volcanic sequences. The deposits in andesite contain considerably less galena than those in the acid extrusives; a small proportion of the mineralization in the latter has texture, mineralogy, and geologic setting analogous to the Captain's Flat copper-Iead-zinc deposit, for which both syngenetic and epigenetic origins have been proposed. Very little copper mineralization occurs within granitic material, even though rocks of this type ranging from Silurian to Carboniferous in age crop out through much of the geosyncline, and the extent of the metal contribution from plutons to the deposits in volcanics is open to question. Numerous deposits are known in the contact zone around Mid-Devonian and Mid-Carboniferous granites, however, and the formation of these orebodies has undoubtedly been influenced by plutonic activity. Small occurrences of copper with associated minor nickel sulphides are developed in a narrow serpentinite belt of possible Lower-Middle Devonian age in the southern section of the Highlands.

Jan 1, 1970

By D R. Wines

The design of near-surface civil infrastructure requires detailed consideration of the geological/ geotechnical conditions, excavation geometry and sequence and ground support measures to ensure stability of the underground openings and minimal impact on overlying or adjacent infrastructure. Twin parallel road tunnels have been designed and built with connecting cross passages and a piggyback busway tunnel as part of a large infrastructure project in Australia. The tunnels were excavated in poor to fair quality rocks using road headers. Temporary ground support includes shotcrete, rock bolts and canopy tubes. Extensive numerical analyses have been performed to analyse the expected behaviour of the tunnels during excavation, including two-dimensional analyses using UDEC and three-dimensional analyses using FLAC3D. Structural defects in the rock are explicitly included in the 2D analyses to examine the potential for localised ground instability. The stress redistribution is captured by the 3D modelling with an accurate representation of the complex excavation geometry and the detailed excavation and support sequence. This paper presents the modelling methodology, numerical results and discussions on integrating both 2D and 3D analyses to achieve reasonable design.

Mar 8, 2011

The Department of Mineral Resources is the lead agency in mine site environment management and control inNew South Wales. The Department introduced a Mining, Rehabilitation and Environmental Management Plan (MREMP) process several years ago in order to integrate the activities of other government agencies who may have a material interest at the mine site. The MREMP process has resulted in a spirit of trust and co-operation between agencies and between agencies and mining companies. The spirit of co-operation has been reflected in greater public confidence that mining is environmentally responsible.  

Jan 1, 1995

By V A. Tsukerman

Prospects a new energy saving method for an efficient destruction of the sturdy and hard materials (rocks, ores, frozen soils, concrete blocks, etc) û the Electric Pulse Discharge (EPD) method of materials destruction for green processing in mining and processing of mineral raw materials are considered.The EPD-technologies give additional possibilities for solving ecological problems at the expense of increase of integrated approach of utilisation of minerals and industrial wastes. The scientific and technical level of executed development of EPD method is sufficient for organisation of design work to develop substantially new equipment. A number of plants have been developed and tested, including plants for processing raw material with minerals of jewels, plants for selection of mica from rocks, and plants for processing the merging of artificial mica.

Jan 1, 2002

By A C. Edwards

The Mongol-Okhotsk belt consists of detached fragments of the Circum Pacific fold belt which have been trapped within the Mongol-Okhotsk fold belt. In its western part, the structures of the belt form an east-facing loop that is not connected with the other orogenic structures of Central Asia. In the eastern part of the belt (the Mongol-Okhotsk suture zone) the terranes form a zone between the Siberian craton to the north and the Bureya composite terrane to the south, that is linked with the Circum Pacific belt. The accretionary terranes, together with their Precambrian backstops, form a series of consistently-stacked, paired units that are bounded by northwest and north trending sinistral strike-slip faults. The ages of the rocks forming these accretionary complexes vary from Late Precambrian - Carboniferous in the west to Cambrian - Jurassic in the east. The terranes developed due to a progressive westward stacking of the accretionary complexes during the process of accretionary growth. The magmatic rocks young eastward indicating that migration of the magmatic front of the arc followed the eastward growth of the accretionary complexes. The accretionary terranes may be differentiated by their Paleozoic lithological assemblages. Only the Selemdzha, Niman, and Kerbi terranes located in the eastern part of the Mongol-Okhotsk suture zone contain significant amounts of black shale, and it is these terranes that host the bulk of the hardrock and placer gold mineralisation that is present within the suture zone. Gold mineralisation is present both as vein style and disseminated mineralisation within structural duplexes.

Jan 1, 1999

By Rogerson R, Queen L

The petrology and age of mid Cretaceous to Palaeogene marine volcanics may provide important clues to the palaeogeography of the period, particularly for tectonic elements and events outboard of the Papuan Basin. This initial survey of known marine volcanics of this age reveals a paucity of reliable data on isotopic ages, geochemistry and syngenetic mineralisation on virtually all units. Existing data allows a tentative subdivision of known marine volcanics into either MORB-like early Palaeogene rifts/ marginal basins, early Palaeogene ensimatic arc rocks overlying ?Late Cretaceous and Palaeogene fore-arc/marginal basin crust, late Palaeogene ensimatic arc rocks, and mid to Late Cretaceous ensialic rift rocks. Due to lack of data, some units are difficult to classify into these categories.

Jan 1, 1991

By T Brown

Australia is now committed to the most significant period of infrastructure investment since the 1960s and the current climate of project finance and public private partnership (PPP) model uncertainty means it is imperative that the affordability and certainty in delivery of infrastructure projects is maximised.In light of the current and forecast levels of infrastructure investment it is worth drawing comparison with a similar period of Australian expansion when the nation’s first railways were constructed. Similarly to over a century ago, we are following a trend in rapid development and are already reaping the inefficiencies that could be avoided with broader technical planning and improved client coordination.The original rail networks were developed by the individual states before they combined to form a Federation of states in 1901. As a result of the adoption of different gauges by 1917 a passenger wanting to travel by train from Brisbane to Perth had to change trains six times.Similarly in 2011, there is little parity between Australian states on the quality requirements (performance specifications) for road tunnels. Differences between states start most significantly with the size of the specified traffic envelopes, thus the size of tunnel required. Where ambiguity and differences exist in project documentation, performance specifi cations (PS) and broad technical requirements for road tunnel projects, any associated risk in interpretation ultimately ends up being incorporated in the bidder’s (constructor’s) final sell price.Whilst not nearly as inconvenient as having to change train at each state border, and largely unnoticed by the general tax paying motorist, this paper examines examples of apparent minor differences in Australia’s recently constructed road tunnels to highlight the differences in road tunnel specifications.The paper identifies how these small differences manifest themselves in major price penalties between projects and further, highlights the need for further specification review, refinement and standardisation across road tunnel jurisdictions to increase road tunnel affordability.

Mar 8, 2011

By M R. Stevens

An approach of geological mapping and descriptive criteria has been used to identify hydrothermal eruption breccias, named the Onemana Breccia. These in part mantle a gold bearing fossil hydrothermal system located on the eastern side of the Coromandel Peninsula, New Zealand. Whilst eruption breccias are documented from active and recent geothermal centres within the Taupo Volcanic Zone and in Northland their recognition at Onemana is the first confirmed discovery for this lithotype within ancient hydrothermal systems of the Coromandel Volcanic Zone. At Onemana the widespread occurrence of silicification, sinters, volcanic lake sediments, eruption breccias and advanced argillic alteration allows classic hot spring epithermal modelling. The geological setting, distribution, lithological characteristics, hydrothermal alteration and trace element geochemistry of the Onemana eruption breccias are described. These breccias are closely comparable with hydrothermal eruption deposits elsewhere, particularly those in active ore forming hydrothermal systems. Consideration is given specifically to the role of the Onemana Breccia in an exploration strategy for discovering epithermal gold-silver deposits.

Jan 1, 1991

By Penrose E. K

With the exception of occasional periods, when up to 80% of oxidized ore was treated, the G.M.K. plant treated all sulphide ore until October, 1939. The treatment was, briefly, as follows:The ore was ground to approximately 17% plus 200 mesh Tyler and agitated in cyanide solution, after straking. After agitation, the pulp passed through two stages of counter-current decantation washing in Dorr thickeners and was filtered once, to complete the precyanidation stage.The precyanide filter cake was repulped with flotation circuit solution and floated in a Denver Sub A flotation machine, consisting of twelve cells. The concentrates were roasted, cyanided and filtered four times before disposal to the' dam. The flotation tailings were thickened to conserve water and pumped away to a separate dam.The average results of flotation operations for the six months before October, 1939, are shown in Table 1.

Jan 1, 1942

By D Cork, R Peet

"Methane is a signifi cant greenhouse gas. Methane is released from coal seams during the mining process, both in surface and underground operations. This uncontrolled release is termed æfugitive emissionsÆ and in underground mines is transferred to the atmosphere in ventilation air, known as ventilation air methane (VAM). The global VAM emissions are over 369 Mt of CO2-e/a (Butler, 2011; US EPA, 2010). Coal mines may abate this VAM or consider abatement should there be a price on carbon. These fugitive emissions are heading towards ten per cent of AustraliaÆs emissions by 2020 (Department of Climate Change, 2011).There are safety issues involved in VAM destruction. Due to the nature of coal, and coalextraction, unpredicted methane spikes above the lower-explosive-limit (LEL) can occur in theventilation air; for example outburst events or ventilation failure. This could lead to a mine fi re ifthe mine ventilation air was connected to a VAM abatement plant and the risks are left unmitigated.CorkyÆs is working with the mining industry to directly address these safety issues. CorkyÆs calltheir technology VAM RAB, which stands for ventilation air methane regenerative afterburner(VAM RAB). VAM RAB utilises the principles of a thermal oxidiser.This paper discusses fi ve independent layers of protection (ILPs) to fi rst stop methane reachingthe thermal oxidiser and secondly prevent the fl ame front from burning away from the VAMRAB. The test work completed or contemplated includes safety integrity level (SIL) assignmentto various vents, barriers and door systems to prevent a fl ammable mixture reaching the VAMRAB, proven rapid response methane monitoring sourced from the petrochemical industry, anddefl agration experiments to test the eff ectiveness of the passive geometry and active engineeringcontrols. These experiments and SIL assessments indicate that it is possible to safely connect theVAM RAB to a working coal mine.Further work is required to upscale the pilot safety work. Refi nement to the design is possible;for example improvement to safety duct controls once trialled at demonstration scale plus thermalenergy capture for power generation or other applications to provide heat. Nevertheless, thispaper shows how safety issues can be managed by a multilayer of protection approach usingvents, barriers and doors, and appropriate thermal oxidiser geometry."

Jun 1, 2012

By I T. Ross

In the last 50 years there have been tremendous improvements in equipment used in development on underground mines. Compressed air powered jacklegs have been replaced by high powered electro-hydraulic drifters on sophisticated drill jumbos and load haul dump units have taken over from small shovels and rail cars.Despite the increase in power applied in key parts of the development cycle, average advance rates have fallen and costs have increased. The factor that is most often regarded as the main contributor to slowing advance rates is increased support requirements. Whilst there is no denying that the drive to improve safety has resulted in the requirement for more bolting and the installation of a skin support (mesh or shotcrete), this is not the only factor.Within the industry as a whole, many of the basic principles of development appear to have been lost over time. This paper looks at a historical case study and discusses some of the features of old development cycles that are no longer in use. This highlights some of the basics that appear to have been forgotten. These may be indicators to what may provide improvements in the conventional drill and blast development cycle.CITATION:Ross, I T, 2014. Development – back to basics, in Proceedings 12th AusIMM Underground Operators’ Conference 2014 , pp 67–74 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 24, 2014