For the second time this month, China's largest producer of aluminum, the Aluminum Corp of China Ltd, or Chalco, announced that it plans to acquire a share of Mongolian coal resources in an attempt to diversify its business.

The company said on Tuesday it will pay $308 million to acquire 29 percent of Winsway Coking Coal Holdings Ltd, which owns Mongolian coal resources. The top aluminum manufacturer will be paying HK$2.12 ($0.27) per share for Winsway, a 13 percent premium to the company's closing price of HK$1.88 ($0.24) on the Hong Kong Stock Exchange on Tuesday.

Chalco bought a controlling stake in SouthGobi Resources Ltd. from Canada’s Ivanhoe Mines Ltd earlier this month, but the sale stalled when the Mongolian government said it was reviewing the proposed change of ownership. South Gobi has four coalmines in Mongolia.

Chalco reported a 69.4 percent drop in profits last year to $37.6 million, from $123.4 million in 2010, largely due to falling aluminum prices.

Industry analysts say that one third of the expenses in aluminum manufacturing is the cost of electricity, so Chalco has looked to acquiring its own sources of energy, such as coal.

Chalco has also been looking to diversify into iron ore. In 2010, Chalco and Rio Tinto Group jointly invested in the Simandou iron ore project in Guinea.