The management of the Ok Tedi gold and copper mine in Papua New Guinea's Western Province has begun sacking employees who are on an illegal strike.
1,500 workers began their stoppage over pay at the start of the month but the action has now been ruled to be illegal.
The company says about 100 employees have returned to work after a request that they do so but many others have refused.
The striking workers are angry that they had not been given bonuses paid to expatriate staff.
The company says the strike has cost it more than 30 million US dollars and puts its future at risk.
In a statement, the Ok Tedi management says it has begun dismissing workers who keep breaching the industrial agreement, their employment contracts and a court order.
It says these workers will receive their entitlements and be repatriated to their home towns.