Petrik, Leslie F.Akinlua, AkinGitari, Wilson M.Akinyemi, Segun AjayiNULLFaculty of Arts2013-07-122024-11-062013/02/112013/02/112013-07-122024-11-062011https://hdl.handle.net/10566/17682Philosophiae Doctor - PhDThe management and disposal of huge volumes of coal combustion by products such as fly ash has constituted a major challenge to the environment. In most cases due to the inadequate alternative use of coal fly ash, the discarded waste is stored in holding ponds, slag heaps, or stock piled in ash dumps. This practice has raised concerns on the prospect of inorganic metals release to the surface and groundwater in the vicinity of the ash dump. Acceptable scientific studies are lacking to determine the best ash disposal practices. Moreover, knowledge about the mobility patterns of inorganic species as a function of mineralogical association or pH susceptibility of the dry disposed ash dump under natural weathering conditions are scarce in the literature. Fundamental understanding of chemical interactions of dry disposed ash with ingressed CO2 from atmosphere, percolating rain water and brine irrigation within ash disposal sites were seen as key areas requiring investigation. The mineralogical association of inorganic species in the dry disposed ash cores can be identified and quantified. This would provide a basis for understanding of chemical weathering, mineralogical transformations or mobility patterns of these inorganic species in the dry ash disposal scenario. The current study therefore aims to provide a comprehensive characterisation of weathered dry disposed ash cores, to reveal mobility patterns of chemical species as a function of depth and age of ash, with a view to assessing the potential environmental impacts. Fifty-nine samples were taken from 3 drilled cores obtained respectively from the 1 year, 8 year and 20-year-old sections of sequentially dumped, weathered, dry disposed ash in an ash dump site at Tutuka - a South African coal burning power station.enCoal fly ashDry disposed fly ashWeathering/ageingUnsaturated weathered ashMineral phasesBulk chemistry Pore water chemistryInsoluble mineral phaseDissolved soluble saltsAcid susceptibilitySoluble buffering constituentsAmphoteric behaviourModified sequentialextraction schemeChemical partitioningMetals mobilityMajor oxidesMajor elementsTrace elementsAnion speciesThesisUniversity of the Western Cape