Environment Minister Sussan Ley has signalled that a landmark court finding on climate change will not stop her from approving new coal mines as she waved through a five-year life extension for a coking coal mine south of Sydney.

The Russell Vale mine extension was the first coal mine approved by Ms Ley since Federal Court judge Mordecai Bromberg found in May that she could breach her duty of care to protect young Australians from climate change if she unconditionally approved an expansion of the Vickery coal mine in NSW.