* Facility would initially process 200,000 metric tons

per year

* Goal to be online before Trump leaves office

* Companies decline to say whether in funding talks with

US govt

* Seabed seen as mineral source; draws environmental

concern

(Adds Cobalt Blue stock movement in paragraph 6)

By Ernest Scheyder and Melanie Burton

March 30 (Reuters) - Deep-sea mining firm Glomar

Minerals and Australia's Cobalt Blue Holdings said on

Monday they plan to build a U.S. refinery to process critical

minerals extracted from the bottom of the Pacific Ocean within

three years.

The move comes amid growing interest in mining the world's

seabeds for supplies of nickel, manganese, copper and other

critical minerals used to build electronics, weapons and a range

of consumer goods, even as the practice has drawn criticism from

environmentalists.

Demand for those minerals is expected to jump in coming

years, fueling a push for new and alternative supplies by

Washington, Tokyo and other governments seeking to counter

Beijing's dominance in the minerals industry.

Glomar and Cobalt Blue plan to choose a U.S. site by June

for the refinery and be in commercial production before

President Donald Trump's term ends in 2029.

That timeline would require the partners to obtain financing

for the facility, which is expected to cost less than $500

million and initially process 200,000 metric tons per year, with

expansion potential.

Shares of North Sydney, Australia-based Cobalt Blue rose

nearly 7% in Monday morning trading on the Australian Stock

Exchange.

The companies declined to discuss commercial terms of their

partnership and whether they are in funding talks with the U.S.

government. No customers have signed supply contracts yet.

"Undersea minerals represent a game-changer to redefine U.S.

critical mineral dependence the way shale oil and gas reshaped

global energy geopolitics," Robbie Diamond, Glomar's executive

chairman, told Reuters.

Rival The Metals Company said last week it is in

discussions to lease Texas land for its own refinery, which is

slated to produce 12 million metric tons per year. Company

officials, though, said that project would be dependent on

funding from the Trump administration.

TECHNOLOGY COULD GIVE BOOST TO INDUSTRY

Cobalt Blue, which is developing a cobalt mine and refinery in

Australia, will supply its technology to separate at least five

minerals from so-called polymetallic nodules.

While mining seabed nodules faces engineering and technical

challenges on its own, the processing of those nodules is also

challenging and no commercial nodule refineries are in

operation. Both companies are essentially betting Cobalt Blue's

technology can help jump-start a new industry.

"Polymetallic nodules offer the prospect of supplying

multiple critical minerals from a single resource stream," said

Andrew Tong, Cobalt Blue's CEO.

Founded in 2025, Glomar controls exploration leases in the

Pacific's Clarion-Clipperton Zone previously held in part by

aerospace giant Lockheed Martin ( LMT ). Glomar is "looking to

expand its resource base," Diamond said, although he declined to

provide details.

INTERNATIONAL TENSION

The refining plans come amid increasing geopolitical tensions

around deep-sea mining. Trump in January said he would

accelerate permitting for companies aiming to mine in

international waters.

The International Seabed Authority - created by the United

Nations Convention on the Law of the Sea, which the U.S. has not

ratified - has for years been considering mining standards, but

again failed to formalize them when it met earlier this month.

Trump's January move aims to bypass the ISA. The Metals Company

has asked Trump to issue its own international permit. Glomar

declined to say whether it has asked the same of the Trump

administration, although it has yet to formally apply for such a

move.