Search Documents

The mineralogy of ten trihydrate bauxites and their leached residues from bomb digestion tests at 140, 180 and 2400C was investigated and the resultsòcorrelated with analytical data. It is shown that increased recovery of alumina at high temperatures is due to. the dehydroxylation of goethiteòrather than the presence of alumina monohydrates. The effects of aluminous goethite -on the interpretation of "available alumina". results-and normative analysis are discussed and it is concluded that,'cautionòmust be exercised in interpreting the results of bomb digestion tests in terms of alumina hvdrates.

Jan 1, 1973

By A Sturgess, P McKenna, P D. Erskine, D Doley, V C. Glenn

For more than four decades, rehabilitated lands in the Bowen Basin have been planted with buffel grass (Cenchrus Ciliaris), which is often used to provide rapid, stabilising and erosion reducing cover to reshaped landforms (Erskine and Fletcher, 2013; Harwood, Hacker and Mott, 1999; Grigg, Shelton and Mullen, 2000; Naidu et al, 1997). Historically introduced to Central Queensland and encouraged by pastoralists in the early 1900s (Humphreys, 1967), the species has been extensively used by mine managers in seeding mixes (Coaldrake and Russell, 1970; Edye, 1975), and the invasive nature of the grass has led to the monodominance in rehabilitated areas of semi-arid Central Queensland. With 40 open cut coalmines in Central Queensland (Department of Natural Resources and Mines, 2015), a considerable amount of land is either disturbed mine footprint (156 200 ha) or rehabilitated (29 200 ha) (Dale, 2015), and the bulk of rehabilitation consists of relatively young (<30-year-old) developing ecosystems, with demonstrated biomass fuel loads up to 20 t/ha (Grigg, Shelton and Mullen, 2000).Uncontrolled fire poses a significant risk to rehabilitated landforms that are located in close proximity to mining infrastructure, neighbouring communities, open pits with exposed flammable coal seams and flammable stockpiled coal resource. Mine lease holders in Queensland have the added responsibility of managing and protecting any endangered regional ecosystem communities, and flora and fauna listed federally under the Environment Protection Biodiversity and Conservation Act 1999 or the State Vegetation Management Act 1999; as well as, any culturally significant sites such as scar trees or middens that are found on-site. Additionally, uncontrolled fire in rehabilitated landscapes poses a significant risk to mine site closure goals, with the potential to create altered states and stalled ecological trajectories (Grant, 2006). CITATION:McKenna, P, Glenn, V, Erskine, P D, Doley, D and Sturgess, A, 2016. Fire behaviour in buffel grass dominated mine site rehabilitation in Central Queensland, Australia, in Proceedings Life-of-Mine 2016 Conference , pp 158–162 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

Copper Recovery from Printed Circuit Board by Carbonisation

Sep 13, 2010

By J Cornejo, A Pinochet, C Caviedes

The ore extraction rate and the incorporation of new areas are key operational parameters. In massive deposits mined by caving techniques they both control the cave back geometry, which is mostly responsible for the induced stress state around productive levels. Early detection of deviations from admissible geometries will prevent stability problems related to geomechanical hazards, helping to improve safety and working conditions and reduce the potential for lost reserves.This paper describes a mine planning tool currently in use at the El Teniente mine. This tool involves the control of the cave geometry based on rules that have been defined as a result of different studies and experience collected during the operational history of the mine.This mine planning strategy achieves an extractive mining process with lower risk than conventional planning methods, ensuring ore reserves extraction if followed as planned while reducing unexpected changes in mining sequences.CITATION:Cornejo, J, Pinochet, A and Caviedes, C, 2016. Geometric control for strategic mine planning at El Teniente Mine, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 191–196 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

The series of events leading to the adoption of more complex flotation circuits for coal have been reviewed. In essence, it has been concluded that ac- ceptable overall flotation recovery will only be obtained when efficient distri- bution of collector over all the component feed size fractions is ensured. The achievement of this goal is most likely to be obtained by feed classification and separate flotation of appropriate size fractions. The adoption of such a phil- osophy, however, imposes a number of process problems of both a chemical and an engineering nature. Some of these problems have been identified and possible solutions discussed. A case is emerging for the development of a new generation of flotation cells designed specifically for the flotation of classified coal and for the development of a series of novel re- agents which have the propensity to float middling particles.

Jan 1, 1984

The Osborne copper-gold deposit (within the Trough Tank project area) is located in the Cloncurry Shire about 195 kilometres south-east of Mount Isa. It is hosted by Proterozoic metasediments of the Eastern succession of the Mount Isa Inlier. The deposit is overlain by 25-40 metres of Mesozoic cover, so it represents a true "blind target". Placer Exploration has 100% outright ownership of the property, having purchased the remaining 10% interest in the property from Shell in early 1993.Intensive exploration, both surface and via drilling at Osborne, has taken place since 1985, when CSR Limited Mineral Exploration and Development Group (acquired by Placer in 1988) entered into a joint venture with Billiton Minerals. Exploration effort from 1985 to June 1988 outlined a 20 kilometre strike length of magnetic horizons, in what was termed the North-East, Central and Southern anomalies, which were drilled with weak indications of copper-gold mineralization in the North-East anomaly. During the later half of 1989, four core holes were drilled into the shallower northern partofthe North-East anomalywhere previous drilling had outlined economic intersections of mineralization. These holes encountered high-grade copper-gold mineralization confirming the potential for an economic deposit to be hosted within the ironstone sequence. Further drilling involving over 400 holes (100 kilometres of drilling) has brought the deposit up to its present resource status.The current resource inventory is 36 million tonnes grading 2.0% copper and 1.0 grams pertonne gold and includes a high-grade zone of 13 million tonnes grading 3.6% copper and 1.5 grams per tonne gold. The discovery of this potential economic mineralization resulted from a persistent exploration effort based on indications that a large mineralizing system existed within a sequence of ironstones.

Jan 1, 1993

The Australian Mineral Industry's growth in the last two decades is directly related to the skill and experience of its consultants in mining, metallurgy, geology, finance, management, marketing, and engineering. The role of mining consultants needs to be re-examined, so that the quality of the service they deliver will continue to be adequate for the 1990's. One means of this evaluation is by examining Case Studies in the strategies and difficulties of developing contract and entrepreneurial research.

Jan 1, 1986

The Bowen Basin coal field is an important energy resource. A relatively small proportion is avail- able by open cut operations. Responsible men throughout the world have warned of the need to increase coal research immediately. Because energy is still available in abundance these warnings have not been heeded in Australia. The characteristics of the Bowen Basin coal make it a fairly difficult underground mining proposition and a significant research effort is required to solve the problems likely to be encountered. Both industry and government have responsibilities in the economic recovery of the maximum proportion of the resource and jointly funded research administered by existing organisations should be inaugurated forthwith.

Jan 1, 1976

By B Arthur, K Sexsmith, D Hockley, S D

At the proposed Crandon Project, mill tailings would be depyritised for upland disposal. The resulting pyrite concentrate would be disposed of in the underground workings as a cement-amended paste backfill. In the long term, the underground workings would be flooded and the potential for the paste backfill to generate acid would be limited. However, while the mine is operational, there is potential for oxygen ingress to the backfill that may lead to sulfide mineral oxidation and acid generation. A series of humidity cell tests were completed to assess the potential for groundwater contamination. To assess effects of surface area on oxidation, the humidity cell tests were conducted on moulded cubes of paste backfill. The tests were terminated at different intervals, and the cubes were dissected and examined mineralogically. Various leach extraction procedures were also used to assess the progress of oxidation and secondary mineralisation within the paste backfill. The test results showed that: the cement amendment significantly contributes to acid neutralisation and results in a lag in excess of one year before the onset of acidic conditions (in comparison to less than three weeks for the pyrite concentrate); the depth of oxidation in the paste backfill is restricted to about 1 mm after 107 weeks of testing; and secondary minerals form a distinct ærindÆ at the surface of the paste backfill. The results indicate that acid generation in the backfilled stopes would be minimal. The importance of including the surface area effect in the testing (ie using moulded cubes) is clearly demonstrated.

Jan 1, 2003

Australia has historically been a world leader in mining innovations. This trend is reflected in the international patent records, which show that in recent years there has been some recovery in the number of patent filings arising from Australian research. These innovations occur across a wide cross-section of mining technologies and derive from both public and private sector research. Australian mining innovations are largely dominated by new processes and equipment, principally in the areas of rock drilling and coring, strata stabilisation, cutting tools, blasting, mine design and oil field exploitation. They include improvements in drill bits, rock bolts and accessories and wellbore systems. Another area that has received significant research attention has been the in situ thermal processing of coal deposits. High profile examples of Australian mining innovations include the æSORDMinerÆ, a remote-controlled mining machine for use in mining collapsing wet environments, and CSIROÆs SMART*CUT rock cutting pick that dramatically increases the rate of cutting hard rock. This paper will provide an overview of recent innovations in Australian mining, as reflected in the international patent records, including the organisations and individuals active in the field, and the technological nature of specific innovations.

Jan 1, 2008

Petroleum exploration is proceed ing in Western Australia at an ever- increasing pace. Results in recent years have been very successful, with the discovery and development of the Barrow Island oilfield and the Dongara gasfield, and the discovery of several major gas-condensate fields on the Northwest Shelf. The Northwest Shelf discoveries will have a big impact on the economy of the State by providing an abundant indigenous source of energy. Prospects for further large dis- coveries are believed to be excellent. The most prospective areas are thought to be on the continental shelf in the Carnarvon, Browse, Perth, Canning, and Bonaparte Gulf Basins.

Jan 1, 1973

Surface oxidation is one of the most important factors that influence the flotation selectivity and recovery in the processing of complex sulphide ores. It is an inherent part of surface chemical reactions that determine whether the surface film formed on a sulphide mineral will act as a hydrophobic or hydrophilic one. Because of the highly complex surface chemistry and mineralogy involved the results of flotation tests may often be difficult to interpret. In this paper, the flotation behaviour of nickel-copper ores processed in the Sudbury area is discussed with emphasis on the effect of oxidation on individual minerals, primarily pyrrhotite. In general, moderate oxidation of a freshly ground ore promotes the flotability of all principal sulphides in the ore leading to a bulk flotation concentrate. The ease of individual mineral flotability under normal aeration conditions, which is chalcopyrite > pentlandite > pyrrotite, changes to pentlandite > chalcopyrite > pyrrhotite under oxygen-deficient conditions. This behaviour is correlated with the catalytic activity of these minerals for oxygen reduction. On the other hand, preferential oxidation of pyrrhotite may lead to a selectivity increase in flotation. Such a behaviour has been noted in the flotation of a pyrrhotite-rich process stream. The results have been discussed in the light of fundamental electrochemical interactions involving pentlandite, chalcopyrite, pyrrhotite, pyrite and grinding media and a mechanism has been proposed to explain the selectivity.

Jan 1, 1993

Coal pillar design has been based on generalised formulae of the strength of the coal in a pillar and experience in localised situations. Stress measurements above and in coal pillars indicate that the actual strength and deformation of pillars varies much more than predicted by formulae. This variation is due to failure of strata surrounding coal. The pillar strength and deformation of the adjacent roadways is a function of failure in the coal and the strata about the coal. When the pillar is viewed as a system in which failure also occurs in the strata, rather than the coal only, the wide range of pillar strength characteristics found in the UK, USA, South Africa, Australia, China, Japan and other countries are simply variations due to different strata-coal combinations and not different coal strengths.This paper presents the measured range of pillar strength characteristics and explains the reasons. Methods to design pillar layouts with regard to the potential strength variations due to the strata strength characteristics surrounding the seam are Presented.

Jan 1, 1998

By Howes PM

In the iron and steelmaking processes, dusts are generated and treated by wet dedust- ing methods to form slurries which are high in iron content, but also contain certain impuri- ties. For many years these slurries have been processed and the wet cake, which is produced, has been dumped because of the high zinc and alkali chloride contents. Sintering is an appropriate process for recycling of these materials, provided the deleterious impurities can be kept under control. Zinc is a deleterious element in blast furnaces because it promotes the formation of accretions on the upper walls of the furnace. This results in irregular furnace performance. Alkali chlorides effect the emissions from the sinter plant waste gas due to the high resis- tivity of these components, resulting in decreased efficiency of the electrostatic precipitator. Experimental work indicated a concentra- tion of zinc in the -11 pmt particle size frac- tion. A cyclone plant was installed producing a "coarse" usable product and a "fine" waste Product.

Jan 1, 1984

Automation in underground mining enhances safety and leads to economic efficiency. In the past many efforts have been made on the automation of longwall shearer operation. With respect to the ultimate goal of automation, ie self controlled operation, coal bed boundary detection is one of the key problems. For longwall human labor is necessary in order to detect the exact position of the coal seam to be excavated. The authors present a sensor concept based on infrared technology and pattern recognition which will solve this problem. The very harsh underground conditions set high demands on the implemented sensors. The combination of infrared sensors and powerful processing algorithms is part of the innovative concept for automation of the new Eickhoff Bergbautechnik GmbH SL 750 shearer loader. The multi-sensor automation system EiControlPlus which is designed for the complete detection of the machine environment fills in the gap in the coal-excavation automation by building a recognition system that turns the shearer loader into an 'intelligent machine' which is capable of detecting the correct position of the seam to be excavated and thus enables human-free coal mining.

Dec 6, 2010

Upgrading and Removing Phosphorus from Low-Grade and High Phosphorus Containing Iron Ores

Sep 13, 2010

By T Rock

This paper looks at recent advances in the United Kingdom (UK) tunnelling industry with particular reference to the A3 Hindhead Project. A 1.8 km long twin bore tunnel is the centrepiece of the A3 Hindhead scheme, which commenced construction in 2007 and is being delivered under a UK Highways Agency early contractor involvement (ECI) contract. The proposed construction methodology is progressive mechanical excavation of a horseshoe-shaped tunnel with shotcrete installed close behind the face using robotic spraying equipment. The tunnelling medium is a æsoft rockÆ sandstone for which there was little previous tunnelling experience, requiring extensive geotechnical investigations and an innovative approach to lining design. A 240 m long section though sandy material utilising a steel pipe umbrella is also required. This paper describes the development of the tunnel planning and design including the most recent developments in UK road tunnels. The innovative approach to the design of the following is discussed:the æpermanentÆ primary lining,an observational technique allowing optimisation of the steel pipe umbrella design,a plain concrete secondary lining designed for resistance to a hydrocarbon fire, anda spray-applied membrane.

Jan 1, 2008

It is a common misconception that the grant of mining tenure, whether it be an Exploration Permit, Mineral Development Licence or Mining Lease, will entitle the holder to access all land within it in order to explore or mine. The ability for miners to access their tenure in order to undertake activities is critical to the industry. While significant time and energy is quite rightly dedicated to resolving native title and cultural heritage issues before the commencement of mining operations, the same cannot always be said for addressing potential impediments that arise as a result of the overlap between mining and other tenures. Miners should be aware of the overlaps that occur with other tenure and the impact of these overlaps on the minerÆs ability to explore or produce from the area. The existence of an overlap with petroleum tenure, nature refuges, national parks, wild river areas or reserves such as aboriginal land leases are all likely to have an impact on the minerÆs ability to access the area and conduct activities. In some instances, such as an overlap with petroleum tenure, Queensland legislation encourages the miner to reach agreement with the holders of the overlapping tenure. However, in other instances, such as an overlap with a national park, mining tenure is unlikely to be granted at all. This paper summarises the impacts and impediments that arise as a result of overlaps of tenure that are likely to affect mining operations. It also provides examples of how these impediments can, if possible, be overcome under Queensland legislation.

Jan 1, 2007

By A L. Bennett

It is well understood that designers and constructors must protect the existing surroundings of tunnel construction, particularly in the selection of excavation methods, ground support and waterproofing systems. However, while this can readily address the existing conditions, the tunnel owner and the designers need to consider the changes that are likely to occur during the life of the tunnel. It is typical for transport infrastructure to have a design life of at least a century. While the effects of constructing the tunnel on its surroundings are a short-term effect, the converse case, the protection of the tunnel, and the need to maintain its integrity, will affect developments over and adjacent to the tunnels beyond the foreseeable future. Decisions made during the design phase have the potential either to facilitate development or to hinder it for the long term.Examples principally from Australia, New Zealand, Singapore and Hong Kong show that the provision for future development is addressed in different ways. These have ranged from making no specific provision, putting the onus onto developers to ensure that the tunnels are not affected adversely, to including a loading allowance for future development in the performance specification or contract documents for a tunnel project.These two contrasting approaches have strong points and risks. A highly prescriptive definition of permissible loadings around the tunnel can provide unambiguous guidance for the approving authority and the developer, but runs the risk of being overly conservative to allow for all the envisaged works, while still missing a detrimental combination of effects that theoretically complies with the specified requirements. In contrast, a general requirement to not cause detriment is open to interpretation and potentially difficult negotiations to reach agreement between the tunnel owner/operator and developer and finally the appointed contractor (probably with no contractual relationship with the tunnel owner).In practice, a combination of prescriptive and performance requirements is likely to provide the optimum combination of clarity and flexibility. The author provides examples and recommendations on how such provisions could be structured.CITATION:Bennett, A L, 2014. Protection of ?tunnels in their future environment, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 495–500 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

Recovery Efficiency Study on Ilesha Placer Gold Ore by Flotation Using Locally-Sourced Frothers and Collectors

Sep 13, 2010