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Environment Protection Authority

Warkworth Mining Ltd convicted and penalised $50,000 for dam wall collapse

Media release: 4 September 2017

The New South Wales Land and Environment Court has convicted and penalised Warkworth Mining Ltd $50,000 for the collapse of a sediment dam wall.

Warkworth Mining Ltd, which is part of the Coal & Allied and Rio Tinto group of companies, operates a coal mine near Singleton in the Hunter Valley.

Warkworth was prosecuted by the Environment Protection Authority (“EPA”) for breaching a condition of its Environmental Protection Licence which required Warkworth to carry out its licensed activities in a competent manner.

The prosecution was in relation to an incident at the Warkworth mine when part of a sediment dam wall collapsed on 5 January, 2016 following several days of heavy rain. Up to 4.4 megalitres of sediment laden water escaped into surrounding areas, including the nearby Wallaby Scrub Road reserve.

The incident occurred after Warkworth had modified the dam to increase its capacity, however, nether the design nor the construction work was undertaken or overseen by an engineer, nor did Warkworth subject the completed works to an appropriate risk assessment or other quality assurance processes. A section of the new embankment wall collapsed when water levels reached the heightened embankment wall for the first time.

EPA Regional Director, North, Adam Gilligan said “The dam wall failed due to a phenomenon known as “piping”, which occurs when circular shaped fissures form in the core of the dam wall due to excessive hydraulic pressure.

“It was estimated that at the time of the dam failure there was approximately 4.56ML of water in the dam.

“It is estimated that the discharge from the dam embankment took up to 18.5 hours.”

“Ensuring that environment protection licence holders carry out their activities in a competent manner is an important part of a regulatory scheme that requires industries to take practical and reasonable steps to reduce their impact on the health of the community and environment” he said.

 “The decision of the Court serves as a warning to all operators to ensure they comply with their licensing requirements and carry out their activities in a competent manner”.

Warkworth pleaded guilty to the offence. In addition to the $50,000 penalty, which is payable to the Environmental Trust for general environmental purposes, the Court ordered Warkworth to pay the prosecutor’s legal costs and to publish notices in the Singleton Argus and the Newcastle Herald detailing the conviction.


Contact: Public Relations

Page last updated: 04 September 2017