PT Aneka Tambang, Southeast Asia's second biggest nickel producer, agreed to pay $66.5 million for a 10 percent stake in Oxiana Ltd.'s Martabe project in Indonesia to add gold and silver production.

Antam, as Aneka Tambang is known, has options to acquire an additional 15 percent of the project, Melbourne-based Oxiana said today in a statement to the Australian stock exchange. In April, Antam said it was in talks with Oxiana to buy a stake.

Output from the $310 million mine is due to start late next year at a rate of 200,000 ounces of gold and 2 million ounces of silver annually. The two companies also signed an accord to study and develop additional mineral deposits in the Southeast Asian nation.

``Antam's expertise and place in the Indonesian mining sector makes it an excellent strategic partner for Oxiana as it aims to expand its business in Indonesia,'' Oxiana said. Antam, which is also bidding for Australian zinc and lead exploration company Herald Resources Ltd., will pay for its share of development costs, it said.

Antam dropped 3.9 percent to 3,100 rupiah at 9:36 a.m. in Jakarta trading. Oxiana fell 5 cents, or 2.2 percent, to A$2.29 at 12:37 p.m. Sydney time.

Oxiana also said today it remains on schedule to start output from the A$1.1 billion ($1.06 billion) Prominent Hill mine in Australia later this year. The mine will double its copper output and boost gold production by a third.