*

Government imposes 48 new rules to protect nearby ancient

rock

art

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Critics say decision will set back climate action

*

Plant and its LNG to generate 4.3 bln tons of carbon

emissions

(Rewrites throughout, adding quotes from environment minister

and reaction)

By Christine Chen

SYDNEY, Sept 12 (Reuters) - Australia gave final

approval on Friday for Woodside to operate the

country's oldest and second-largest liquefied natural gas plant

until 2070, while imposing 48 "strict" new rules in a bid to

limit its environmental impact.

The decision to extend the life of the North West Shelf

plant in Western Australia caps a seven-year approvals process

dogged by appeals and backlash from green groups, who say it

will imperil nearby ancient rock art and set back efforts to

curb climate change.

The federal and state governments had to balance those

concerns with the interests of one of Australia's largest export

industries, which is the biggest source of LNG for key ally

Japan.

Environment Minister Murray Watt said on Friday Woodside had

agreed to 48 conditions that were "technically feasible" but

would protect the Indigenous Murujuga rock art in the area by

limiting emissions.

"Some of the gases that are emitted at this facility,

which if not controlled properly, could have a significant

impact on the rock art," he told reporters.

"We are confident that the conditions that we've set are the

right ones to protect the jobs in and the economic opportunities

arising from the plant but also importantly to protect the rock

art."

The rock art is estimated to be up to 50,000 years old and

is of cultural and spiritual significance to Indigenous

Australians. It was inscribed on the UNESCO World Heritage List

in July.

Watt also set additional legal protections for parts of

the site under federal heritage law, while ensuring "this

decision does not stop industry from operating".

The North West Shelf plant's existing licence had been set

to expire in 2030.

The four-decade extension was given preliminary approval in

May, but Woodside then battled with the government over the

conditions for nearly four months.

Watt said Woodside had agreed to specific limits on

pollutants, including cutting levels of nitrogen oxide emissions

by 60% in five years and 90% by 2061.

Rock art experts have said such emissions risk degrading the

petroglyphs by turning into acid rain.

"This final approval provides certainty for the ongoing

operation of the North West Shelf Project, so it can continue to

provide reliable energy supplies as it has for more than 40

years," said Liz Westcott, Woodside's chief operating officer

for Australia.

The company was committed to protecting the rock art, she

said.

'CARBON BOMB'

Critics condemned the decision as a blow to Australia's

efforts to curb climate change, with the plant and its LNG

expected to generate up to 4.3 billion metric tons of carbon

emissions over its lifetime.

"It is a betrayal of Australians who voted for action on

climate change, and of our Pacific neighbours," said Mark Ogge,

principal advisor at The Australia Institute.

The Australian Conservation Foundation said the conditions

were inadequate in preventing "climate damage" caused by the

plant, calling it a "carbon bomb".

The North West Shelf LNG plant was Australia's largest until

July, when Woodside shut one of its five processing trains,

reducing its capacity to 14.3 million metric tons a year as the

offshore gas fields that long fed the plant are drying up.

The extension lays the groundwork for Woodside to bring

online new supply, including its Browse offshore project, the

country's biggest untapped conventional gas resource.

Woodside's partners in the North West Shelf venture are

units of BP, Chevron ( CVX ), Shell, Japan's

Mitsui & Co ( MITSF ) and Mitsubishi Corp ( MSBHF ), and China's

CNOOC.

Woodside shares closed down 3.4% with oil prices falling.