Oct. 17 (Bloomberg) — BHP Billiton Ltd., the world’s biggest mining company, said a strike at the company’s Spence copper mine in Chile entered a fifth day.

Copper output at the Melbourne-based company’s 200,000-ton-a-year mine continued at a slower rate, spokesman Ruban Yogarajah said today in a telephone interview from London.

Unionized workers at Spence, near the northern city of Calama, walked out Oct. 13 after rejecting a wage offer. Yogarajah wouldn’t comment on ongoing negotiations.

Melbourne-based BHP produced 172,685 tons of copper at Spence in the 12 months through June 30 and plans to reach full capacity of 200,000 tons in the coming year, the company said Sept. 14.