The NSW Environmental Defenders Office representing the Bulga Milbrodale Progress Association lodged a summons in the Land and Environment Court requesting the Court declare invalid the Planning and Assessment Commission (PAC)  review granting approval for the Warkworth Mine Continuation Project .

PAC handed down its review approving both Rio Tinto's Warkworth and Mount Thorley mines expansion plans on November 26 last year.

Bulga Milbrodale Progress Association will argue in its appeal that PAC in arriving at its decision to approve the Warkworth Project has fallen into legal error.

The Association says PAC failed to consider what would happen if the endangered ecological community -  Warkworth Sands Woodlands actually became extinct as a result of the expansion.

"The group argues that PAC did not fulfil its duty to consider the environmental impacts of the Project because of this," according to The Bulga Bugle released today.

Their second ground is that the Chief Executive (CEO) of the Office or Environment and Heritage (OEH) and the PAC misconstrued and failed to apply the NSW Biodivserity Offsets Policy for Major Projects.

And, their third ground is that the CEO OEH in granting certification for the project was tainted by 'apprehended bias'.

This latest appeal marks the second time the Association has taken Rio Tinto to the Land and Environment Court.

Their first appeal was successful with the Land and Environment Court's Chief Justice Brian Preston rejecting the project due to its adverse impacts on the environment including the Warkworth Sands Woodlands and the Bulga community.

He handed down his decision in April 2013 subsequently Rio Tinto appealed the decision in the NSW Supreme Court. The full bench of the Supreme Court upheld the Land and Environment ruling the following year.

The Association say they must act now to ensure that Warkworth Mine and the Planning Minister are held accountable to the laws that protect the environment.

A spokesman for Rio Tinto said “We note an appeal has been lodged against the decision by the independent Planning Assessment Commission to allow mining to continue at Mount Thorley Warkworth."

“The current consents were approved after a thorough and robust process in which all opinions were heard and considered. This included two public hearings, a public meeting and numerous calls for public comment, with the most recent resulting in more than 2800 submissions in support of a strong future for Mount Thorley Warkworth.

“The Planning Assessment Commission found that the significant benefits of allowing mining to continue outweigh the potential impacts and that our applications were consistent with current government policy, particularly in relation to biodiversity, noise, air quality and socio-economic impacts.”