Drilling mud content revealed
Environment Southland yesterday signed off a consent to deposit 160 cubic metres of Greymouth Petroleum drilling mud onto a Bluff property.
Graham Laidlaw applied for the consent to discharge water-based and synthetic-based mud, which was used during gas exploration at Horseshoe Bay, Stewart Island, to his Ocean Beach property.
The contents of the mud could not be released last month as it was considered commercially sensitive. However the contents were revealed when the discharge was approved yesterday.
The application says the hydrocarbon waste is made up of drilling mud and natural rock cuttings, sediments and soil.
The water-based mud contains caustic soda and M-I Gel (bentonite), and the synthetic-based mud contains lime and barite.
It would be deposited by landfarming, a process of spreading waste onto land and incorporating the waste into the soil and then resowing the area to allow natural bioremediation to occur.
The application says there are no groundwater bores or surface water bodies on the site.
Mr Laidlaw said Greymouth Petroleum approached him, and while it had covered the transport costs he was not paid to take the mud.
It had been used in Taranaki with good results, he said.
He would use the waste to stop the sand hills on his property from blowing away.
The consent was the first of its kind for Environment Southland and they had sought advice from the Taranaki Regional Council which had issued 14 drilling waste discharge consents.
Mr Laidlaw's consent, which includes a large number of conditions, including soil, surface and groundwater monitoring, discharge limits and reporting requirements, has been issued for 18 months.
- © Fairfax NZ News
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