Mar. 29 -- China Tin Group Co., the country’s second-largest maker, signed an agreement with Aluminum Corp. of China and Grirem Advanced Materials Co. to develop rare-earth resources in Guangxi, according to a statement.

The company will set up a joint venture with Chinalco, as Aluminum Corp. of China is also known, and Grirem Advanced Materials, a rare-earth mining company, according to the statement posted on its website today, without giving details.

China is the world’s biggest exporter of rare earths, which are 17 chemically similar elements.