UPDATE 1-Thai Banpu plans 5 bln baht bond issue in Q4

(Adds details, investment plan)

BANGKOK, Aug 14 (Reuters) - Thailand's biggest coal miner, Banpu BANP.BK, said on Thursday it planned to sell around 5.0 billion baht ($149 million) of three-year bonds in the fourth quarter of this year as part of its debt refinancing plan.

The firm was also considering converting short-term loans worth 9 billion baht into long-term debt with a maturity of more than three years, Chief Finance Officer Somrudee Chaimongkol told reporters, without elaborating.

"The debt refinancing will be completed in the fourth quarter of this year," Somrudee added.

The short-term loan was taken for its acquisition in June of a 78.4 percent stake in China's Asian American Coal Inc (AACI) for $420 million to add to its coal reserves, Somrudee added.

Chief Executive Chanin Vongkusolkit said Banpu was drafting a five-year investment budget for 2009-2013, but he declined to unveil the figure, adding 60-70 percent of the budget would be used for the coal business and 30-40 percent for electricity.

With the investment plan, Banpu aimed to grow more than 15 percent per annum, Chanin said.

The firm also maintained its coal sales target of 20 million tonnes this year, after reporting 8.8 million tonnes of sales in the first half, he said.

"For 2009, we are aiming higher. Sales could be more than 20 million tonnes due to growing demand, while coal prices should still be high," Chanin said.