SANTIAGO, June 18 (Reuters) - Anglo American's copper

output at its Los Bronces mine in Chile is expected to fall

nearly a third from average historical levels next year as the

miner pauses a processing plant for maintenance, the company's

Chile head said on Tuesday.

Anglo American previously said it would suspend the plant,

which is the smaller and older of two at the site, in mid-2024,

but had not disclosed the estimated hit on production.

Los Bronces is Anglo American's flagship copper mine,

representing about a fourth of its copper output worldwide,

which spans several sites in Chile and Peru.

Demand for the red-metal has surged worldwide, and BHP

made an unsuccessful $49 billion offer for rival Anglo

American this year in a play for its smaller rival's

copper mines.

The maintenance on the processing plant is expected to take

at least a couple of years, said Patricio Hidalgo, CEO of Anglo

American in Chile, at an event.

"It will depend on the input and the ore grade, so it's not

one-to-one, but it's about 30% as of next year, compared to what

we historically have produced," he told reporters.

Anglo American is aiming to compensate for falling

production levels dinged by hard, lower grade ore, and hopes to

start new extraction in 2027, after delays due to permitting and

other factors.

Suspending the processing plant, called Los Bronces, will

give the company time to move ahead with preparations for new

extraction phases, including securing an additional water supply

and moving the Perez Caldera tailings dam.

"It opens a window for us," Hidalgo said. "We have to see

when the optimal window of time is to remove the dam."

Los Bronces is majority owned by the miner's local unit,

Anglo American Sur, with a stake just over 50%. A joint venture

between Japan's Mitsui ( MITSF ) and Chile's state-run Codelco

owns nearly 30%, while Japan's Mitsubishi ( MSBHF ) owns the

remainder.