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A major by-product of coal fuelled electricity generation is ash – fly ash and bottom ash. Bottom ash is collected from the bottom of the boilers while fly ash is an inert mineral matter collected in dust collection plant. There is currently a modest market for fly ash reuse as a cement replacement up to 30% by volume as well as in road construction and other uses. Delta continually reviews opportunities to recycle fly ash.
Mt Piper fly ash is transported by conveyor to a nearby disused open-cut mine. Ash from the bottom of the boilers is collected and trucked to this repository for dry disposal.
Wallerawang Power Station fly ash and bottom ash is collected and placed at the Kerosene Vale Ash Repository which is located about 2.5 km north-east of the power station. Ash is hauled to the repository by trucks along a private haul road from the power station. As they are filled, the mounds of ash deposited in the repositories are progressively covered with earth and revegetated as part of an extensive rehabilitation program.
Click on the link to view the Kerosene Vale Ash Repository – Stage 2 Consent Conditions
At Vales Point Power Station, ash is transported by wet sluicing to the ash dam. In a contract arrangement, ash is collected from the outlet of the fabric filter hoppers and transported to an onsite facility where it is processed for sale. The excess is then wet sluiced to the ash dam.
Bottom ash is collected at the ash dam from the wet sluice stream for processing and sale. Cenospheres, the minute floating particles that drift around the ash dam, are also harvested and processed for sale. The Vales Point ash dam is divided into separate ponds and as each pond reaches capacity, it is capped and revegetated.
At Munmorah Power Station, the bottom ash is disposed of in the Munmorah ash dam and the flyash is disposed of in the Vales Point ash dam.
Continuous monitoring and rigorous environmental management programs are designed to minimise the impacts of ash storage at all Delta locations.
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