Shares in Aughinish Alumina owner Rusal rose 9% to reach their highest since April after US sanctions were lifted, as the importance of the Limerick plant in the global metal supply chain was laid bare.
The US Treasury officially lifted sanctions on Rusal and other companies linked to controlling stakeholder Oleg Deripaska, the Russian billionaire accused of having close ties with the Kremlin.
Aluminium prices fell 2% after the sanctions were lifted as the second biggest producer of the metal became free of the shackles imposed on its business.
Rusal controlling company En+ said Mr Deripaska’s shareholding has been cut from 70% to 44.95% and his voting rights further cut to 35%.
His assets remain frozen and he will not be able to receive any dividends from En+, the firm said.
The company made public a letter sent earlier this month to Democratic Senate minority leader Chuck Schumer in order to free its business interests, signed by ambassadors from Ireland, Austria, France, Germany, Italy, Sweden, the UK, and the EU.
Aughinish Alumina in Limerick was vital to almost one-third of Europe's supply of alumina, the letter said.
"Aughinish Alumina has produced alumina on the banks of the Shannon in Limerick since 1983 and contributes €130m to the local economy.
"It was acquired by Rusal in 2007, but is operationally independent from its parent company and maintains an Irish workforce and Irish management team.
"Aughinish is critical to the European alumina and aluminium industries, providing approximately 30% of the continent’s total supply of alumina used by smelters across Europe.
"Closure of the facility would therefore result in extensive job losses across the EU while damaging other key downstream industries," the letter said.
The US imposed crippling sanctions on Mr Deripaska's business interests and halved Rusal’s value in the process last April.
Full statement by Tánaiste @simoncoveney and Government Ministers on confirmation by US authorities that Aughinish Alumina is no longer directly impacted by US sanctions is available @ https://t.co/kdkwsC2fY0. pic.twitter.com/wBJkcmUKA2— Irish Foreign Ministry (@dfatirl) January 28, 2019
Shares in Rusal plummeted as sanctions reverberated across the entire aluminium industry as it scrambled to restore supply chains.
Global mining firm Rio Tinto has plants in France and Iceland that use the Irish alumina, and Liberty House Group’s Scottish smelter also depends on the site.
Despite stiff resistance from members of both President Donald Trump's Republican Party and the Democrats, US Treasury Secretary, Steve Mnuchin signalled his intent to end the sanctions this month, saying their intention was never to damage companies like Rusal, but to punish Mr Deripaska personally.