Recasts first paragraph, adds Rio Tinto response in paragraph 6, share moves in paragraph 9

April 4 (Reuters) - An Australian mining union said on Friday iron ore giant Rio Tinto RIO.AX agreed to amend its policies including flight delay compensation to benefit workers at the Paraburdoo project in the Pilbara region of Western Australia.

The Mining and Energy Union $(MEU.AU)$ said that Rio Tinto, the world's biggest iron ore producer, will now compensate its "Fly-In, Fly-Out" (FIFO) workers heading home with A$500 ($313.55) for delays exceeding four hours and A$1,000 for delays over 12 hours.

The amendment came after more than 400 workers at the Paraburdoo project signed a majority support petition to initiate bargaining for a collective agreement for the first time in over two decades.

Paraburdoo mine is part of Rio Tinto's Western Australian operations, and employs around 16,000 employees, the company website showed. The MEU is a part of the Western Mine Workers Alliance (WMWA) along with the Australian Workers Union.

The support petition was currently being assessed by the Fair Work Commission (FWC), the industrial relations tribunal, the MEU said. If the FWC grants orders for collective bargaining, Rio Tinto will be forced to the negotiating table.

"We are aware the Australian Workers Union has filed an application to the Fair Work Commission," a Rio Tinto spokesperson said in an emailed response to Reuters.

"We will engage with the Fair Work Commission process and continue to talk directly with our people."

The iron ore miner will also now fully fund national FIFO for up to 30% of their rail crew workers and hike the training allowance for on-job trainers to A$7,500 per annum from A$5,600.

The MEU has also secured retention bonuses for all of BHP's rail crew members worth A$10,500 regardless of their classification, it said.

Shares of Rio Tinto RIO.AX ended 0.5% up, while BHP closed 0.7% down.

($1 = 1.5946 Australian dollars)

(Reporting by Rajasik Mukherjee in Bengaluru; Editing by Rashmi Aich and Mrigank Dhaniwala)

((Rajasik.Mukherjee@thomsonreuters.com;))