AT 4pm today, the last raw material will be poured into the blast furnace at Corus Teesside Cast Products (TCP) and the mothballing process will begin.

Although most of the 1,600 workers facing redundancy should remain at the plant, near Redcar, east Cleveland, for months yet while the mothballing is carried out, the symbolic significance of the moment cannot be understated.

Dave Nicol, 46, the plant’s director of asset management, who is overseeing the mothballing, said the whole operation would take about six months to complete.

The shutdown of the blast furnace is being carried out in a specific way to ensure it can be restarted again as quickly as possible should a buyer for TCP come forward.

Once the last of the raw material has been poured into the 2,200 C inferno, it will take about 20 hours for the furnace to empty, a process known as the blowdown.

On Saturday evening, the process known as “tapping the salamander” is expected to begin.

This involves creating two holes to drain – or “tap” away – a pool of residual liquid that gathers at the bottom of the furnace.

It is called the salamander by steelworkers because mineral elements in it create a particularly bright colouring.

After that, the furnace will begin to cool down.

Despite the symbolic significance of shutting down the furnace, Mr Nicol said: “At all times, the remit we are working to is that we must take it off safely, but be able to restart it as quickly as we can.”

He said planning had been carried out to ensure each part of TCP was maintained in the best condition possible.

This had involved Corus experts, supplier experts and even in some cases going back to the equipment manufacturers to seek advice.

Mr Nicol said: “We have had to look at each piece of equipment and see what is the correct way to stop it.”

The process being used has been carried out successfully before on other Corus blast furnaces, which were later brought back online.

Mr Nicol said: “The whole focus of the mothballing arrangements is to make sure we can prevent any deterioration of the plant.”

During the blowdown, there may be some noise and steam emitted from the top of the blast furnace, but Corus stressed there was no reason for residents to be alarmed.

Mr Nicol added: “We are doing everything we can to minimise any noise. There may be some noise for short periods of time on Saturday.