BEIJING/SHANGHAI- A rare earth subsidiary of state-run Aluminium Corp of China (Chinalco) in Guangxi has repeatedly violated pollution rules and contaminated land, the environment ministry said.

Chinalco must investigate the problems and make corrections, the ministry said.

Chinalco "sincerely accepted" all requests from the inspection team and will "resolutely rectify" the violations, it said in a statement.

It has sent a working group to its Guangxi subsidiary to supervise the work, it said.

This month, a government environmental inspection team found affiliates of Chinalco subsidiary Guangxi Nonferrous Rare Earth Development Co Ltd had failed to properly rectify violations.

The firms had "seriously polluted the surrounding environment", the Ministry of Ecology and Environment (MEE) said in a statement published on Wednesday.

Guangxi Nonferrous was previously punished for environmental violations in 2018 along with a Chinalco subsidiary in northwestern China. 

The MEE statement said some mining projects run by Guangxi Nonferrous' units exceeded their approved limits and built outdated and illegal production facilities.

"The inspection found ... obvious problems of legal violations, chaotic environmental management and relatively large environmental risks at the Guangxi rare earth company," it said.

China began a nationwide environmental auditing programme in 2016.

It was expanded to giant state-owned companies such as Minmetals, which was accused of being a "big corporate bully" in 2017 after failing to fix repeated violations.

The latest round of audits included the China National Building Materials Corp, and found that one of its subsidiaries had not only failed to rectify violations but also tried to cover them up, the MEE said in a separate statement on Wednesday.

As of Sept. 20, environmental inspectors had handled 6,047 complaints, issued 46.7 million yuan ($6.85 million) in fines and detained 30 people during this round of audits, the environment ministry said.

($1 = 6.8195 yuan)

(Reporting by Min Zhang in Beijing and David Stanway in Shanghai; editing by Jason Neely) ((min.zhang@thomsonreuters.com; (8610) 5669-2105;))