0.49 Adaro Energy 2012 Annual Report English

DELIvERINg POsITIvE ENERgY 110 low wall design. Coal exists further down dip and has been estimated as inventory coal. By deinition, inventory coal includes both coal resources and tonnages of coal which are not considered economic. AEI estimated that MIP holds 258 million tonnes of non-resource inventory coal within the measured, indicated and inferred categories, which may be eventually transformed partially into resources by the consideration of new extractive technology such as underground mining or underground gasiication. JORC Coal Reserves: At the time of publication of this report, a new mining study of MIP was under way but had yet to be completed. AEI interrogated the new geological model with the February 2012 Marston studys pit shell and came up with an in situ resource tonnage of 282 million tonnes, which was within 2 of the Marston 2011 JORC Resource igure of 286 million tonnes, albeit with a slightly lower strip ratio. given that this is within our accepted error of estimation, the CP has decided to retain the Marston 2012 JORC Reserve tonnage of 273 million tonnes until a revised Reserve study is completed later in 2013. PT Bhakti Energi Persada JORC Coal Resources: Adaro Energy owns a 10.22 share in BEP, and has signed a three-year options agreement under which we may choose to acquire another 79.8, bringing our ownership to 90.02. All 2012 BEP tonnages in this report assumed that Adaro Energy has exercised that option. BEP published a JORC coal resource estimate of 9.53 billion tonnes based on an independent study in 2009. BEP, through its seven operating companies, has since drilled 500 additional holes, and AEI has now reviewed BEP’s geological and topographic data and estimated JORC-compliant coal resources using JORC 2012 methodology. AEI revised the radius of the inferred resource polygons down to 1,000 meters and applied the Preston sanders density correction to reduce the in situ coal density from that previously used. AEI has also applied a policy where a minimum of three points of observation were required to deine a resource polygon. AEI assessed the total in situ coal tonnage for all seams to be 7.96 billion tonnes. The BEP coal resources are low rank, with a total moisture of 46.9, ash of 3.1 on an as-received basis, and a caloriic value of 3,354 Kcalkg on an as-received. Total sulphur is low at 0.10 on an as- received basis. For details see table on page 108. JORC Coal Reserves: Adaro Energy is still working towards the deinition of a coal reserves statement for BEP but is not ready to issue any forward-looking statements beyond the existence of 7.96 billion tonnes of JORC coal resources. Details of the AEI estimate of BEP’s JORC-compliant resources can be seen in the table on page 106. IndoMet Coal Project In 2010, Adaro Energy acquired a 25 interest in the IndoMet Coal project in Central Kalimantan. BHP Billiton owns the remaining 75. JORC Coal Resources: In its 2012 annual report BHP announced total metallurgical coking coal and thermal coal resources of 774 million tonnes. There has been no update of this number. The table on page 106 breaks down the resources as at June 30, 2012. Adaro Energy JORC-Compliant Coal Reserve Quality Air Dried Basis Operating Company Locality Coal reserve quality calculated as at Dec. 31, 2012 Moisture in the analysis sample adb Ash adb Volatile matter adb Total sulphur adb Calorific value Kcalkg adb PT Adaro Indonesia 1,2 Tutupan 17.4 2.8 40.8