(ShareCast News) - BHP Billiton said it was targeting another $600m in coal production costs by the end of the 2017 financial year.BHP also increased its forecast for coal output for the current year to 43m tonnes, with plans to lift production to 46m tonnes in 2018."While cost compression has been evident across the industry, we continue to work hard under our new operating model to improve our performance," said BHP Billiton Minerals Australia president Mike Henry."Even in today's difficult environment, all of our operations remain cash positive."Against the backdrop of greater uncertainty in the outlook for thermal coal, we are confident that base demand in emerging economies will remain resilient for decades to come and our higher quality coals position us well in an increasingly carbon constrained world."