Premier Jay Weatherill has today announced a $514 million investment by Nyrstar guaranteed by the State Government securing the future of the redevelopment of the smelter.   

Nyrstar will put in $103 million direct funding on top of $120 million raised through a transaction for the forward sale of silver output from the new smelter. 

The total  state government contribution has increased to a $291 million third-party funding guarantee with risk management supported by the Federal Government's Export, Finance and Insurance Corporation.   

This is because the project has "increased in size" to include both a sinter and acid plant, with construction to begin next year and fully operational by 2016. 

The redevelopment will also be supported by a 10-year $50-million Targeted Lead Abatement Program

Mr Weatherill said without this investment, "there would not be a future for the plant in Port Pirie".  

Nyrstar chief executive Roland Junck was also in the city for the announcement, along with Treasurer Tom Koutsantonis, Regional Development Minister Geoff Brock and other company executives.   

Minister Brock said the announcement would bring back certainty in the Port Pirie community and spoke about his passion for Nyrstar, where he worked for 30 years. 

"I don't want to see this community go down," he said.

"I think this community is the best in South Australia if not the world.  

"The current Government has been absolutely fantastic... council has been supportive, it's a matter of everyone taking credit.  

"This is a regional town that has global significance."

Mayor Brenton Vanstone said Port Pirie's future is now secured for at least 50 years.  

"Just imagine if the reverse was happening and the company was announcing either a closure or downgrade of the facility," he said. 

"To be announcing a major transformation which gives economic certainty to the city for the next 50 years, is indeed a momentous and pivotal occasion."  

Minister Tom Koutsantonis said Port Pirie's best days are ahead of them.  

He said Prime Minister Tony Abbott and Liberal Member for Grey Rowan Ramsey "should have been standing here with us".  

"They are not here, and shame on them," he said.