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Scotland Island, Pittwater: Authorities investigate ugly drill spill in water

An ugly brown substance is being cleaned up off the northern beaches after an underwater drilling incident on Pittwater.

An image from a drone showing the extent of the ugly brown drill spill at the southeast end of Scotland Island caused when “drilling mud” leaked during construction of a tunnel for an underwater power cable. Picture: NSW Fire & Rescue (Forestville)
An image from a drone showing the extent of the ugly brown drill spill at the southeast end of Scotland Island caused when “drilling mud” leaked during construction of a tunnel for an underwater power cable. Picture: NSW Fire & Rescue (Forestville)

Authorities are investigating the cause of a large ugly spill of drilling lubricant that has stained a large area of Pittwater.

The so-called “drilling mud”, which contains Xanthan gum, is being cleaned up around the south east end of Scotland Island.

A Rural Fire Service crew lays down booms to help contain the spill. Picture: NSW Fire & Rescue (Forestville)
A Rural Fire Service crew lays down booms to help contain the spill. Picture: NSW Fire & Rescue (Forestville)

The spill occurred at an underwater tunnel being built to link a new Ausgrid power cable from the mainland, at Church Point, to the island.

The NSW Fire and Rescue hazardous materials unit, based at Forestville, was called in on Thursday afternoon and is back at the scene of the spill this morning.

Authorities are trying to contain the spill at the southeast end of Scotland Island. Picture: NSW Fire & Rescue (Forestville)
Authorities are trying to contain the spill at the southeast end of Scotland Island. Picture: NSW Fire & Rescue (Forestville)

Fire and Rescue said the brown, cloudy substance, used as a drilling lubricant, was not toxic.

NSW Environment Protection Authority (EPA) officers are also there today along with NSW Maritime and Ausgrid staff.

Volunteers from the Rural Fire Service helped place booms in the water yesterday to contain the spill.

The “drilling mud” between wharves on Scotland Island. Picture: NSW Fire & Rescue (Forestville)
The “drilling mud” between wharves on Scotland Island. Picture: NSW Fire & Rescue (Forestville)

Fire and Rescue said the spilt substance was used to break down mud, and other matter, to make it easier to pump out when drilling for essential services.

“It makes the mud silty plus highly miscible (allows liquid to completely dissolve in another liquid solution) though the product is still heavy and settles.”

The EPA said it was investigating the discharge of drilling fluid near Scotland Island which created a visible plume.

“Containment measures are in place and the clean-up continues,” EPA director of regulatory operations metropolitan, Giselle Howard, said.

“It is a sensitive marine environment, however the spill has largely been contained and there are no known impacts on aquatic life so far,” Ms Howard said.

Ausgrid said that the drilling contractors, Dunstans, had advised it that the biodegradable drilling mud has been contained and the clean up should be completed over the weekend.

Authorities are cleaning up a chemical spill in Pittwater, at the southeast end of Scotland Island. Picture: NSW Fire & Rescue (Forestville)
Authorities are cleaning up a chemical spill in Pittwater, at the southeast end of Scotland Island. Picture: NSW Fire & Rescue (Forestville)

An Ausgrid spokesman said favourable wind conditions have kept the mud largely confined to the near shore area and away from the seagrass.

“The mud was released by Dunstans who are contracted to Ausgrid to undertake essential work to improve reliability in the area,” he said.

“EPA and other government agencies were immediately notified.

The clean up will continue over the weekend. Picture: NSW Fire & Rescue (Forestville)
The clean up will continue over the weekend. Picture: NSW Fire & Rescue (Forestville)

“Dunstans have put in place a remediation plan for the remaining clean-up in consultation with the relevant Government agencies.”

The work by Dunstans are completing is part of Ausgrid’s project to install a new electricity cable between Church Point and Scotland Island to improve the reliability of the power supply.

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Original URL: https://www.dailytelegraph.com.au/newslocal/manly-daily/scotland-island-ugly-brown-substance-spill-stains-pittwater/news-story/f22360eaee538aa633a01fc6a1f9a7cd