Rio Tinto’s Cloud Peak Energy coal unit raised $459m in an IPO at $15 a share, below its forecast range, reports Bloomberg. Cloud Peak, the third-largest US coal producer, had sought $16 to $18 a share, according to regulatory filings. Cloud Peak will begin trading on Friday in New York. UK and Australian-listed Rio will retain a 48% stake in Cloud Peak, which plans to sell $600m of senior unsecured debt.