Summary:
The Waterberg Complex includes the Grootegeluk mine and the Thabametsi Project.
Grootegeluk
Grootegeluk is located in the Waterberg coalfield and the coal seams are from the Volksrust and Vryheid formations.
The upper part of the coal deposit, the Volksrust Formation (approximately 60m thick) is classified as a thick interbedded seam deposit type, comprising intercalated mudstone or carbonaceous shale and bright coal layers. The Vryheid Formation (approximately 55m thick) forms the lower part of the coal deposit and comprises carbonaceous shale and sandstone with interbedded dull coal seams varying in thickness from 1.5m to 9m. It is therefore classified as a multiple seam deposit type.
These coal seams are subdivided into 11 coal zones, further divided into separate coal and non-coal samples for analysis. A total of 77 samples are analysed per full succession drill hole. The Volksrust Formation consists of 30 coal samples and 30 non-coal samples whereas the Vryheid Formation consists of 13 coal samples and four non-coal samples.
The Zoetfontein fault forms the boundary of the Waterberg coalfield in the north and the Eenzaamheid fault forms the boundary in the south. The Daarby fault, with a throw of some 350m, divides the coalfield into a deep north-eastern portion and a shallow south-western portion. On average, the first fresh coal in the shallow south-western portion is 20m below surface. The lowermost coal seam (Zone 1) occurs at a depth of about 130m in the shallow portion of the coalfield, but this may vary depending on the local structure. The predominantly horizontal coal-bearing formations have a very gentle dip to the south-east near Grootegeluk. Only a few dolerite dykes outcrop in the south-eastern portion of the Waterberg coalfield, and no sills have been encountered in any exploration drill holes drilled in the mining right area to date.
Grootegeluk is experiencing increased geological structural complexities as the pit advances westwards. The new geological model, to be introduced in 2025, will aide in addressing this issue.
Thabametsi
The Thabametsi Project is located in the Waterberg coalfield and forms part of the larger Waterberg coal complex geological model.
The upper part of the coal deposit – the Volksrust Formation (approximately 60m thick) – is classified as a thick interbedded seam deposit type, comprising intercalated mudstone or carbonaceous shale and bright coal layers. The Vryheid Formation, approximately 55m thick, forms the lower part of the coal deposit and comprises carbonaceous shale and sandstone, with interbedded dull coal seams varying in thickness from 1.5m to 9m. It is therefore classified as a multiple-seam deposit type.
The geology is similar to Grootegeluk’s, but practical mining practice requires a different bench configuration. In the north, the full succession of the Volksrust and Vryheid formations are present. However, further south, the Volksrust Formation thins out and eventually disappears. A pertinent channel sandstone in the northern portion of the project area affects benches 9A and 9B.
The Zoetfontein fault forms the boundary of the Waterberg coalfield in the north while the Eenzaamheid fault forms the boundary in the south. The Daarby fault, with a throw of some 350m, divides the coalfield into a deep north-eastern portion and a shallow south-western portion. On average, the first fresh coal in the shallow south-western portion is 20m below surface. The lowermost coal seam (Zone 1) occurs at a depth of about 130m in the shallow portion of the coalfield, but this may vary depending on the local structure. The predominantly horizontal coal-bearing formations have a very gentle dip to the south-east near Grootegeluk. Only a few dolerite dykes outcrop in the south-eastern portion of the Waterberg coalfield, and no sills have been encountered in any exploration drill holes drilled in the mining right area to date.