The project, with investment totalling more than 3 billion yuan ($456.04 million), is expected to contribute more than a fifth to global output once production is in full swing, the Yunnan Daily said.

Yunnan Tin will shut its old smelting units after the new project goes into normal operation to avoid any production disruption, the company said in a filing to the Shenzhen Stock Exchange on Wednesday.

It had begun planning to relocate its smelting capacity as early as 2013, in response to tougher environmental curbs and to ensure sustainable development.

But the full commissioning of the project is uncertain, the company added, including whether it can meet targeted production and standards. It did not elaborate.

China produced 160,000 tonnes of refined tin in 2019.

($1=6.5783 Chinese yuan renminbi)

(Reporting by Min Zhang and Shivani Singh; Editing by Vinay Dwivedi and Clarence Fernandez)