Matla is in the Highveld Coalfield, immediately south of the Witbank Coalfield. The Coalfield is host to up to five coal seams contained in the middle Ecca group sediments of the Karoo supergroup. The stratigraphic sequence in the mine area includes five coal seams that can be correlated with seams found in the Witbank Coalfield. The principal economic seams currently exploited are S2 and S4L, with mining of S5 terminated in 1998 due to high levels of contamination and subsequent increase in abrasivity. The S2 at Matla is well developed in the NW part of the lease area, near mines 2 and 3. It thins out to the south, where thickness averages 1,0 to 2,5m. Qualities are also generally poor in this area, thus S2 is not mined in the southern portion of the lease area. S4 is generally well distributed throughout the lease area.

The best qualities on S4 are on the southern part of the lease area. However, S4 is heavily intruded by dykes in this area, making mining a serious challenge.

Coal seams in the area are generally flat and continuous, with subsequent igneous activity resulting in displacements and devolatilisation of coal seams at places. Matla is divided into two main geological domains, marked by the sill intrusion that underlies S2 but transgresses through and overlies that seam while underlying S4 on the south-western part of the reserves. This sill has burned and devolatilised S2 on the southern part of the mining area.

Matla is in the Kriel district of Mpumalanga, some 20km west of Kriel, 50km south-west of eMalahleni and 30km south of Ogies. Matla is an underground operation with three mines – mine 1, mine 2 and mine 3 – all supplying coal directly to Eskom’s Matla power station by conveyor belt.

Mining at mine 1 was stopped in 2015 due to pillar instability. The impact of this is the continued drop in production and overall qualities being slightly lower than customer specifications.

Matla Mine 1 is an underground bord and pillar mine, which mines the 4 seam.

Matla Mine 2 utilises both bord and pillar an total extraction coal mining methods to mine the 2 seam and proposes to mine the 4 seam in future. Total extraction of a wall in the northeast area is currently underway, but bord and pillar mining may also be utilised in that area if required.

Matla Mine 3 previously utilised bord and pillar method coal mining to mine the 4 seam. It is proposed to extend the current total extraction mining methods at Mine 3 as well as the mining of the 2 seam in future.