The concessions lie in the Barito Basin of Central Kalimantan. The Barito Basin is defined by the Meratus Mountains to the east and separated from the Kutai Basin to the north by a flexure parallel to the WNW-ESE orientated Adang Fault.

Field Exploration identified lower quality Warukin coal seams in the core of a syncline, grading to higher quality Montalat coal seams toward the outer edges of the structure. The Tanjung Formation geology within the TKS Concessions is less well understood because exploration has been limited to coal outcrop mapping. It is expected that coal seams discovered in the older Tanjung Formation will have a higher calorific value and generally better quality characteristics than the younger Warukin and Montalat coal seams.

The main features in the concessions are a syncline structure over the main deposit area with relatively flat dips and younger sediments in the central part of the deposit and steeper dips in relatively older sediments, around the outer edges. Major faults are interpreted surrounding the deposit and controlling the boundaries of the coal to the north, south and east.

The deposit at TKS Concession contains approximately 19 modelled coal seams of which 4 have been split into upper and lower plies. The cumulative coal average thickness is 14.85 m in 19 seams.

The coal seams dip shallowly in the centre of the syncline to 5 degrees and up to 20 degrees around the edges. Steeper old sediments, containing higher-grade coal seams occur around the edges of the deposit where the geological structure is complicated by possible faulting.

TKS Ampah
The TKS Ampah coal concession area lies in the Barito Basin of Central Kalimantan, one of the largest coal-producing regions of Indonesia. According to the published geology, the lease is within an anticlinal structure containing the Tanjung and Montelat formations and Warukin Formations. These rocks are Eocene to Middle Miocene in age and are well known to contain extensive seams of thermal coal. Based on the work to date, a more likely interpretation of the regional geology is that the deposit area is in a syncline where relatively thick seams of Warukin age coal, are surrounded by hills containing older coal seams of the Montelat Formation.

The main features in the concession is a syncline structure over the main deposit area with relatively flat dips and younger sediments in the southern part of the deposit and steeper dips in relatively older sediments in the northern part of the deposit.

The TKS Concession has been subject to detailed exploration since 2005 onwards. The exploration activities were targeted to confirm the occurrences of coal seams found by initial exploration campaigns.

The TKS Concession is proposed to be mined as open-pit excavations by truck and shovel method by contractors.

The mining operation at TKS Ampah commenced during 2018 and uses standard truck and excavator method which is a common practice in Indonesia. Waste material is mined using hydraulic excavators and loaded into standard rear tipping off-highway trucks and hauled to dumps in close proximity to the pits or to in-pit dumps where possible. For the Reserve Statement, it is proposed that contractors will be used for mining and haulage operations over the life of mine.

The TKS Ampah Project is designed as a source for supplying coal to power and cement plants. TKS Ampah Mine was commissioned in 2018 and is planned to have a peak capacity of 0.2 Mtpa. Mine was placed on care and maintenance in 2019.

The purpose of the mine plan was to create a mining sequence that ensures reliable delivery of the coal product to the ROM stockpile from road haulage to the barging point. The mine plan scenario has targeted ramping up production rates for 5 years of mining operation based on the direct input from TKS Ampah. The annual coal supply was optimised based on the minimum required energy of 6,322 kcal/kg (gar) within the mined Coal Reserve tonnage. This plan had to be accounting for the practical mining constraints to ensure the sufficient working room and the dump capacity to accommodate all waste material mined at each stage plan. Monthly and quarterly fluctuations in waste removal, coal exposure and inventory levels will need to be managed through the short term planning process.

Initial box-cut will be developed by mining the waste material using relatively small-sized (50t operating weight) hydraulic excavators, loaded onto standard rear tipping off-highway trucks then hauled to ex-pit dumps in close proximity to the pits. After sufficient mined out space created, the mined waste will be subsequently dumped in-pit using haul back methodology and the ex-pit dump area is then rehabilitated. Coal mining will be undertaken by small-sized (34 ± 40t) excavators with flat-bladed buckets to ensure the minimum dilution and greater mining recovery.

Waste and coal haul roads at the mine would be designed and constructed to be three times wider of the largest size haul truck planned to be used on site. It is proposed to use HD465 (Komatsu Brand) or equivalent for this project. This truck has an overall width of 5.4 m and typically requires 30 m haul road width (including the ditches and safety berms on each side of the road) for operating safely. The in-pit ramp would be constructed to a maximum gradient of 8%, although 10% is reasonably acceptable for short term ramps or short sections of the ramp.
- Width of pit ramp operating 22 m
- 8% ramp gradient
- 1 m sewer width

PT TKS Ampah project has very simple coal production chain where coal is cleaned and mined at the pit using small-sized excavators (a combination of PC200 or equivalent) and hauled by a combination of P124CB and CWB520 classes or equivalent (rigid body off-highway) coal trucks to ROM stockpiles. The average haul distance from the coal face to the ROM is approximately 4 km over the mine life.

The average coal quality attributes of the coal seams considered are sufficient to be marketed as a medium CV thermal coal for domestic power generation purposes.

Coal will be sold from the stockpile area in an uncrushed form (as mined), hence no crushing facilities are planned to be constructed at River Jetty for TKS Ampah project. The stockpiles will be the coal selling point where the ownership of the coal transfers from TKS Ampah to customer.