SANTIAGO: Employees at two giant northern Chile copper mines that produce over four percent of the world's copper voted to end their two-day strike, accepting a bonus and salary increase offer.

The 5,600 employees of the Chuquicamata and Mina Sur mines, owned by the world's biggest mining concern Codelco, would return to work at 5:00 am (0800 GMT) Wednesday and "consider the employers' offer has been accepted" after the eight-hour vote, union leader Jaime Graz told AFP.

Codelco was offering a 4.0 percent wage hike and a bonus payment of 24,000 dollars, with the contract to last 38 months. Union members endorsed the plan with a 68 to 31 percent vote.

The miners had considered previous offers insufficient, noting the high cost of living in the city closest to the mine and the harsh working conditions in the middle of the desert, 2,800 meters (9,190 feet) above sea level.

The walk-out, which saw the participation of 95 percent of the work force, came as copper prices hit a 17-month peak Monday at 7,536 dollars per tonne.

Since early last year, copper prices have rocketed by more than 130 percent, spurred upward by signs of global economic recovery after the steep worldwide downturn.

Although the price of copper fell significantly during the global economic crisis, it increased sharply in recent months amid renewed demand from China, the world's largest copper consumer.

Chile had a copper output of some 5.3 million tonnes in 2008, and was estimated to have produced a similar amount last year, accounting for about one third of global production.

Codelco produces around 1.6 million tonnes of copper per year.