Peru’s Cia Minera Antamina has signed a three-year wage contract with its miners to prevent a strike at one of the world’s biggest copper and zinc mines.

Negotiations over wages have been taking place since July when the previous agreement expired.

Under the agreement Antamina’s 1,080 workers will receive a 4.7% wage hike in the first year, followed by a 4.4% hike in the second and third years of the contract, the miners’ union said.

The contract provides a one-time average signing bonus of $15,000 per worker in addition to health benefits and training.

Miners have conducted strikes in Peru, Chile and Mexico throughout the year to increase their share in the company’s earnings.

Antamina also plans to expand its mine to increase processed ore by 38% to 130,000t per day.