The mothballing of the Corus plant in Redcar marked the end of more than 150 years of steelmaking on Teesside
The process of decommissioning the Corus steel plant on Teesside is beginning in earnest.
More than 150 years of steelmaking in the area ended on Friday when the giant Redcar blast furnace was shut down.
The move will mean the loss of at least 1,600 jobs, with unions preparing to take industrial action.
Decommissioning is likely to take about six months, with any potential buyer expected to have to spend up to £50m to restart the furnace.
Over the weekend the last liquid iron will be removed from the blast furnace at the Teesside Cast Products (TCP) site.
Then holes will be drilled into the hearth to remove all residual metal from the blast furnace - a process called tapping the salamander.
The first job losses will take place at the end of February, with about 300 posts going. The remainder will go over the course of the following three months.
Union leaders have threatened to cause "maximum damage" to Corus over the way they claim the firm has handled the situation.
The Community Union - the biggest representative of Corus workers - said any industrial action would be planned to severely damage the Indian owners Tata.
It said up to 8,000 jobs would be lost in the wider community as a result of the mothballing.
General Secretary Michael Leahy said: "Tata Corus have walked away from Teesside.
"We know that there are a number of good faith offers on the table, yet Tata Corus are not interested.
"A redundancy from a mothballed plant is the same as a redundancy from a closed plant.
"We will be seeking to make surgical strikes that will cause maximum damage to Tata Corus and minimum damage to our members."
Meanwhile, the GMB said Corus staff across the UK, including those at Port Talbot, Scunthorpe and Rotherham, would also be balloted.
Some workers attended a rally on Friday, where family members and well-wishers joined them in an emotional protest outside the site.
A brass band played as around 300 people gathered to mark the end of an era.
TCP has been under threat since last May, when an international consortium pulled out of a 10-year contract.
The mothballing was confirmed earlier this month, despite hopes that a buyer could be found in the meantime.
Some workers have accused the government of talking "platitudes" over the future of the plant, despite £60m being pledged to the area by Business Secretary Lord Mandelson.
Stephen Readman, a 46-year-old fabricator from Middlesbrough, said: "The atmosphere here is devastating. You just feel as if you are going to a funeral.
"It's as if there has been a long illness and now there's some finality.
"We hope it is a proper mothball and that the company are genuine and that this plant can be restarted because we do believe that there are credible people out there who want to take this plant over."
Redcar Labour MP Vera Baird said she was aware of three potential buyers, although she admitted there was only a "30% chance" of a deal being sealed.
Electrician Bob Stainthorpe, 59, from Eston, Middlesbrough, has had 39 years' service at Corus.
He said: "A lot of people are stood on the brink of an abyss wondering what's going to happen to them in the future."
Speaking on Thursday, Business Secretary Lord Mandelson maintained the plant would be protected by the company, with a view to reopening once a buyer has been found.
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