JAKARTA, Jan. 9 (Xinhua) -- Indonesia's shipment of copper ores from Grasberg mine, the world's second largest copper mine, will drop significantly this year due to lagging of production for shifting of operation to underground from open pit mining, a senior official said on Wednesday.

Exports of copper ores from the mine are estimated to drop to 200,000 tons this year, from 1.2 million tons last year, Yunus Saefulhak of the Energy and Mineral Resources Ministry said.

Growing domestic demand also contributed to the downshift. This year a total of 1 million tons of copper ores will be used for domestic use, up from 800,000 tons last year, according to the official.

Grasberg mine, situated in Indonesia's eastern Papua province, is also the world's largest gold mine and has been taken over by Indonesia's state-owned PT Asahan Aluminum since Dec. 21 from U.S. giant Freeport McMorant after the U.S. operation since 1973.

Production of copper ores from the mine is forecast to drop to 1.2 million tons this year from 2.1 million tons last year, the official said.

"Outputs of ores this year will ratchet down due to the transition from open pit mining to underground mining," Yunus said.

The decline of production is expected to continue next year as the firm has to make preparation in infrastructure among others, he said.

"There will be a process that must be weathered, such as constructing infrastructures facilities and building roads," he said at the ministry.