China's state reserves authority said Monday that the country would release the fourth batch of national reserves of copper, aluminum, and zinc this year.

Some 30,000 tonnes of copper, 70,000 tonnes of aluminum, and 50,000 tonnes of zinc will be released from the national reserves in early October, the National Food and Strategic Reserves Administration announced.

Only processing and manufacturing enterprises of copper, aluminum, and zinc will be eligible to bid, and the purchased metal shall be used for production promptly. It shall not be resold or hoarded, said the administration.

Since the beginning of this year, bulk commodity prices have surged due to factors including the overseas spreading of COVID-19 and the imbalances of supply and demand, causing pressure on medium and small firms.