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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Kerrie brings you Sunday night's forecast
Flying Scotsman travelled alongside three modern trains to celebrate the "past, present and future" of Britain's railway this morning.
Rain develops overnight into Monday before colder and stronger air digs in from the north - bringing the risk of snow, frost and ice