http://nova.newcastle.edu.au/vital/access/services/Feed ${session.getAttribute("locale")} 5 http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:12166 Highly abundant and rich in Mg (R₀₀₂=2.46), ultramfic serpentinites of the Great Serpentite Belt, New South Wales (NSW), Australia, represent one of the best potential feedstocks for ex-situ mineral sequestration. Mineral sequestration mimics natural, exothermic weathering reactions that transform Mg- or Ca-rich silicates into thermodynamically stable carbonates, promising to be an important factor in the sequestration of anthropogenic CO₂ emissions. The Attunga magnesite deposit, near Tamworth, NSW, formed through carbonation of ultramafic serpentinite rocks at shallow crustal levels and represents a natural analogue to mineral carbonation. Study of natural analogues complements experimental studies and assists in the advancement of economically viable and energy efficient processes for large scale industrial implementation of mineral sequestration. Rock textures suggest that carbonation was the result of dissolution/re-precipitation processes by low temperature, meteoric-derived fluids under near-surface pressure conditions. The alteration of serpentinised olivine mesh cells is identified as the primary mechanism of progressive magnesite vein formation in the early stages of carbonation and the inferred crystallisation sequence is used to interpret fluid evolution. 2012-12-06T00:02:03.604Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:12073 New South Wales requires a range of sequestration options for its annual stationary emissions of C0₂ from energy generation. With inadequate sequestration capacity in depleted hydrocarbon reservoirs or porous aquifers at requisite depths for supercritical injection, mineral carbonation is an additional method of sequestration for carbon dioxide emissions. Mineral carbonation replicates the natural weathering process of magnesium-rich silicate rocks to form principally insoluble magnesite (MgC0₃), binding C0₂ chemically in a form that is stable over geological time. The reactions are exothermic, and occur naturally over extended periods. This study assessed the properties of the ultramafic rocks of the Great Serpentine Belt between Bingara and Barraba, NSW, for their mineral carbonation potential. Although dunites have the fastest reaction time and highest conversion rate, the more abundant serpentinites, although hydrated, are attractive targets for mineral carbonation. Serpentinite volumes calculated to a maximum mineable depth of 500 fil have the potential to sequester ex situ more than 300 years of stationary emissions for NSW at 2007 levels. Geomagnetic modelling indicates serpentinites extend to 2 km depth, which may add significant in situ sequestration capacity. Current research aims to decrease the overall cost of storage of C0₂ in serpentinite from $70 to $40 per tonne of net fixed C0₂. Costs will be offset with saleable end-products such as magnesite refractories, magnetite separated during processing, chromium in the form of chromite and spinel, nickel as an accessory element in serpentine minerals, as well as silica and exothermic heat. Commercially viable mineral sequestration requires the carbonation reaction rate to be accelerated. Current research focuses on reducing energy penalty by accelerating the aqueous weathering reactions occurring naturally in serpentinites and pursuing biologically-mediated sequestration by microbes. 2012-11-20T06:02:03.511Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:11954 This project aimed to assess the potential of the Clare Sandstone, a saline aquifer in the Bando Trough and northern Murrurundi Trough, southern Gunnedah Basin, as a reservoir for sequestration of carbon dioxide emissions from coal-fired power generation. Reservoir characterisation of the unit, including determination of accurate storage volume, depends on thorough knowledge of its porosity and permeability, including petrographic analysis to delineate diagenetic influences. Framework grains are predominantly Lachlan Fold Belt sourced plutonic and metamorphic quartz, lithics and minor feldspar, with sporadic influences from New England Fold Belt volcanics. Kaolinite, illite and illite-smectite are the principal clays, which tend to inhibit porosity by blocking pore spaces and coating pore walls. Diagenetic history from textural relationships among cements indicates quartz overgrowths occurred first, followed by siderite, ankerite and calcite cement, then dawsonite (NaAlC₃(0H)₂) and finally, kaolinite. Dawsonite present in the Bando Trough, likely precipitated from permeating C0₂-rich fluids from nearby intrusive activity, and is useful as a natural analogue for geosequestration. SEM observations show the cements and diagenetic clays have acted to inhibit porosity and permeability by blocking pore throats. The study identifies the Clare Sandstone as a highly variable sedimentary unit with some potential as a geosequestration reservoir. More accurate determination of geosequestration capacity depends upon more detailed knowledge of the unit thickness, porosity, permeability, formation depth and salinity in the depocentre of the Murrurundi Trough. 2012-11-09T00:17:05.356Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:9490 Australians are among the world’s largest human per capita contributors to carbon dioxide emissions. In 2008 the most populous state of NSW accounted for 158.2 Mt of these emissions, with 76 Mt of NSW emissions from stationary sources, such as power plants. NSW has not located adequate porous and permeable sedimentary basins to sequester carbon dioxide in underground reservoirs. Mineral carbonation is an alternative method of reducing emissions of CO₂ by chemical reaction with magnesium or calcium-bearing rocks to form insoluble carbonates, which bind CO₂ in a form that is stable over geological time. Current methods seek to replicate the natural weathering process of silicate rocks such as peridotite and serpentinite to form carbonates such as magnesite, but reduce the time for the carbonation reaction to proceed. New processing approaches focus on environmentally sustainable aqueous reactions which eliminate the use of acids, and biodissolution of reactants or precipitation of products using bacteria, which would reduce the energy penalty. Value-added byproducts which could offset costs include magnesite, magnetite, silica, heat, nickel and chromite. Refractory magnesite bricks are currently used for a variety of steel-making and other furnaces, and potentially for insulated housing. The aim is to approach the estimated cost of geosequestration,which is possibly grossly underestimated due to inherent variability of each individual basin. Mineral carbonation should be evaluated in NSW, and other countries where geosequestration is a less than viable option in the short term. The mineral carbonation process represents a stable solution to storing carbon dioxide, without risk of leakage, without the need for monitoring and with the promise of products which will make the process economically viable. 2011-11-28T23:50:10.112Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:6276 Fifteen people with very diverse backgrounds were interviewed and were asked to test one of two mobile non-voice terminal devices, The participants were people who were Deaf or had a hearing or speech impairment. The interviews with some Deaf and hearing impaired participants were signed in Auslan and videotaped. The study reports detailed differences in their uses and needs, places these in the context of their current patterns of communication and argues for technologly development that provides for the rich array of requirements, uses and possibilities. 2010-05-19T06:00:01.130Z ]]>