Aluminum Corp of China Ltd, known as Chalco, said on Thursday its chairman Lu Dongliang had resigned from his position, with former company president Ao Hong put in temporary charge.

Lu informed the board of Chalco, the listed arm of state-owned aluminium firm Chinalco, that he was stepping down as chairman and director due to a "work re-allocation," according to company filing to the Hong Kong stock exchange, which said the resignation was effective immediately.

Lu, 46, has also left his position as vice president of Chinalco, a spokesman for the group said.

It was not immediately clear what Lu's next career move would be.

Once the point man for Chalco's Boffa bauxite project in Guinea, he rose rapidly through the ranks at the company, becoming president in February 2018 and earning promotion to the top job of chairman only 12 months later.

His resignation comes ahead of China's annual meeting of parliament starting on May 22. The gathering in Beijing, taking place later than usual due to the coronavirus outbreak, often coincides with a reshuffle of personnel in key government positions and state-run enterprises.

Chalco said that to ensure normal operations it had appointed Ao, 58,who served as president of the company until 2018 and remained a director, as acting chairman until a successor to Lu is elected by the board.

"During his term of office, Mr. Lu was diligent and responsible, and strived for reform and innovation in carrying out effective work for the company's transformation and upgrading, reform and development," Chalco said, hailing his "outstanding contributions" to the firm.

(Reporting by Tom Daly; Editing by Simon Cameron-Moore)