Summary:
4 key prospective areas were identified in the South Block. These sub-blocks are:
- Muara Lakitan (“ML”);
- Belani (“BL”),
- Batukucing (“BK”) and
- Ampalau coal deposits
The late Miocene to Pliocene Muara Enim Formation is the main coal-bearing formation present in the South Sumatra Basin. The thickness of this formation, in the area around Muara Enim and Lahat, is around 500-700m.The thickness of individual coal seams varies with the thickness of the formation, typically varying between 10 m to 30 m in thickness, with shallow marine clays at the base, and shoreline and delta plain facies (sand, clay, coal) at the top.
Muara Lakitan (ML Block)
The deposit has multiple coal seams with up to ten seams identified from Seam 200 to Seam 1050, in descending stratigraphic order (denoted I_200 to I_1050 respectively for modelling purposes) with multiple subseams and seam splits.
The in-situ coal is of lignite rank, with high Total Moisture (average TM 36.2%), low Calorific Value (CV 5,015 kcal/kg air-dried basis), low ash (average 5.3%) and low sulphur (average 0.3%).
Seam dips are relatively consistent in Muara Lakitan and are typically of the order of 15 to 20 degrees to the northeast. The Muara Lakitan is bounded to the north and south by major northwest trending transverse faults and is sub-divided into a number of sub-blocks by smaller-scale subparallel faults.
Belani (BL) Sub-block
The deposit has multiple coal seams with eleven different coal seams and their sub seams identified at Belani. These seams have a combined strike length of over 4km.The main seams out of the total package have been named as E420, E410, E660, E720, E710, E820, E810, E920, E910, E1000 & E1100 (in descending stratigraphic order). Out of these coal seams, the two thickest seams, Seam 420 and Seam 910, have an average thickness of 5.28m and 12.05m respectively.
The in-situ coal is of the sub-bituminous rank of estimated product quality with high Total Moisture (average TM 28.5%), moderate Calorific Value (CV 5,484 kcal/kg air-dried basis, adb), low ash (average 5.7%) and low sulphur (average 0.4%).
The Belani deposit is bounded to the north and south by major northwest trending transverse faults. Seams generally dip to the east at approximately 23 degrees.
Batukucing (BK) Sub Block
The Batukucing coal deposit is believed to be of Miocene age. The coal exists within the Maura Enim Formation. A total of 16 seams have been identified with a number of plies (seam splits) identified. 13 of these plies have been identified as viable, within the Batukucing tenement, occurring over a strike length of over 4km.These coal plies have been named: E300, E420, E410, E500, E600, E720, E710, E820, E810, E920, E910, E1000 and E1100 (in descending stratigraphic order). Out of these, B600, B710, B810 and B910 average 2.7m, 2.4m, 2.7m, and 3.6m in thickness respectively, whilst other target seams typically range from 1.0m to 2.5m.
The in-situ coal is of sub-bituminous rank, with average in situ coal quality as follows: Total Moisture (TM) as received is 32.4% (ar), Calorific Value (CV) gross as received is 5,433 kcal/kg (adb), Ash is 8.0% (adb) and Total Sulphur (TS) is 0.6% (adb).