Aug 12 (Reuters) - Australia's Stanmore Resources said on Friday it would buy the remaining 20% stake in a metallurgical coal venture in Queensland from Japanese trading house Mitsui & Co for $380 million.

The deal, which the coal explorer plans to fund through internal resources, comes months after it agreed to buy BHP Group's 80% stake in the venture for up to $1.35 billion.

Stanmore, majority-owned by Singapore-listed Golden Energy and Resources, said the deal would cement its position as a leading metallurgical coal miner in the Bowen Basin.

"Having 100% control of South Walker Creek and Poitrel, as well as Wards Well and other projects, allows Stanmore to maximise value amongst our assets in the region," said Chief Executive Officer Marcelo Matos.

The Australian firm said it expects to continue to have sufficient internal sources to meet its ongoing cash needs and fund the deal without issuing new debt or raising capital.

Stanmore expects the venture, now renamed as Stanmore SMC Pty Ltd, to shortly declare and pay a significant dividend. The deal is expected to close in the fourth quarter of 2022. (Reporting by Upasana Singh in Bengaluru; Editing by Aditya Soni)