The Environment Protection Authority said the licence would be renewed for another year but with increased conditions, including a requirement for the company to update its environment improvement program and improve wastewater emissions.

EPA chief executive Tony Circelli said Nyrstar had recorded good lead-in-air results over the past year.

"This has resulted in the best emissions outcome seen from Nyrstar over recent years," he said.

"In order to continue these improvements, in the new licence the EPA has introduced a 12-month average lead-in-air goal to help drive Nyrstar towards long-term performance achievements.

"Similar to the targets in the existing licence, the goal is not designed as an enforceable limit, although it will be a metric for Nyrstar to consider its ongoing performance and the need for further investment and improvement for the operations."

As part of its environment improvement program, Nyrstar will also be required to assess mercury generation and emissions from its operations consistent with Australia's ratification of the Minamata Convention on Mercury.

Australian Associated Press