Chinese state-owned aluminum group Chinalco has signed a deal to invest 19 1/2 billion dollars in mining giant Rio Tinto.
Rio Tinto is the parent company of Alcan Rolled Products of Ravenswood.
The deal is meant to secure resources for China while helping cut Rio's heavy debt.
It's the biggest overseas investment by a Chinese company to date.
Rio shares in London tumbled as much as 18-percent Friday over investor worries that Rio was giving up too much interest in valuable mines.
But outgoing Rio Chairman Paul Skinner defended the deal, saying it was suitable for the times.
Earlier this month, Alcan laid off 168 workers at its Jackson County facility, which is the county's largest employer.