The strike, which helped send copper prices to a 17-month high, is expected to be short-lived as workers are due to vote on a revised offer from the company on Tuesday and most appear to favour a deal.
"Spirits have calmed and I think that tomorrow it is very probable the offer will be approved," said Hector Milla, a union leader.
About a third of the unionised workers at the Chuquicamata and Mina Sur mines refused to turn up for work on Monday.
The mines together account for four per cent of the world's copper production.
Union leaders said 95 per cent of the work force at the two mines joined the strike, the first at the Chuquicamata complex since 1996.
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Putting principles before profits
See also Sydney Irresistible and Mike Hitchen Unleashed
Putting principles before profits