Remediation of Fire Ash Stockpile in Amberley's Hurunui District

Environment Canterbury is to oversee the remediation of an approximately 1,750m3 stockpile of residual fire ash and capping in Amberley in the Hurunui District. The stockpile on the site is the remains of a fire that in 2021 consumed automotive tyres and has been capped with a layer of soil over plastic sheeting.

The objectives of the remedial works, as covered by the RAP, is to mitigate potential risks associated with burnt tyre ash by removing both the ash and the capping material from the site. To achieve this, the stockpile containing approximately 1,300 m3 of mildly contaminated capping material and 450 m3 of ash material will be excavated and disposed off-site to an approved landfill whose waste acceptance would be met.

The 450m3 ash would require treatment to meet the waste acceptance at either Kate Valley, Taiko Landfills or any other approved landfills whose waste acceptance criteria would be met. The stockpiled material was placed on ground surface and is approximately 1.5 m in height.

Therefore, remedial excavation beyond ground surface (i.e., 200 mm depth) will be required to ensure contaminated ash and soil are removed and the soil remaining in place meets the NESCS (2011) human health soil contaminant standards for rural residential land use. The site investigations indicated that the 1,300m3 capping material meet the waste acceptance at the Burwood Recovery Park without treatment.

The capping material could also be disposed at any of the managed approved facilities whose waste acceptance criteria would be met.