Archie Anderson suffers from Cerebral Palsy and has difficulties walking. But a £50,000 operation in St Louis Hospital, Missouri, could give him a chance.
The workers, who are being made redundant, have donated their entire social fund to three charities - one of which is Archie's charity.
The donation from the Rio Tinto workers brings his total to more than £45,000.
Marie Anderson, Archie's mother, has tweeted: "Thank you so much to the workers at Alcan for your wonderful donation to Archies Dream."
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Cool and cloudy Monday with outbreaks of rain. Drier, brighter and warmer from Tuesday
The band played a hit-packed set including Everyday I Love You Less and Less, Ruby and I Predict a Riot.
The police force say events taking place over the bank holiday weekend will still see an increased police presence.