2.2 Cost of sales $2,139 million decreases by $162 million or 7%, which was a net result of an increase of coal sale volume by 4% and a decrease in average cost per tonne compared to last year. Indonesia mine’s average cost per tonne was reduced by $3.49 which mainly caused from a decrease of stripping ratio (BCM : coal tonne) from 11.50 to 9.76 and production cost saving program that has been continuously implemented since last year. For Australia mine’s average cost per tonne decreased by A$3.43 as a result of a better of production performance by 1.38 million tonnes than last year. In previous year, it faced underground mining’s geological problem and delayed in Mandalong’s longwall relocation. In addition, there was a planned Longwall changeover at Mandalong mine, resulting in production stoppage during August to mid of September 2013.