Overview

Mine Type	Open Pit
Status	Active
Commodities	Coal (thermal)
Mining Method	Truck & Shovel / Loader
Production Start	...
Snapshot	Nndanganeni Colliery already has an existing opencast pit with associated mining infrastructure. The proposed void / pit extension will allow for the continuation of the box cut opencast mining with a roll-over rehabilitation sequence.

Deposit type

• Sedimentary

Summary:

The Nndanganeni extension is underlain by rocks from the Karoo Supergroup. The site is also situated in the Witbank Coalfields which is the most important coal-producing coalfields in South Africa. Five coal seams exist in the coalfield, but not all are economically viable. These coal seams are hosted in Vryheid Formation the middle Ecca Group sediments. The number 1 seam is the lowest or deepest while the 5 seam is the uppermost coal seam. The number 2 and 4 seams are the most exploited throughout the Witbank Coalfields.

The Karoo Supergroup mainly consists of sedimentary successions of sandstone, shale and coal. The Ecca Group is underlain by the Dwyka Formation which consists of tillites and diamictites. Geological features such as dykes (dolerite intrusions) and faults are commonly found in the coalfield. The dolerite intrusions typically act as groundwater flow barriers due to their low permeability, while the contact zone of the intrusions acts as flow pathways due to cracks and faults leading to higher flow rates along these contact zones.

In the Nndanganeni project area, the Vryheid Formation directly overlies the Damwal Formation of the Rooiberg Group (Bushveld Complex). The Dwyka Group is absent or not well developed. As the Vryheid Formation pinches out in the study area, the thickness of the formation is only several tens of meters. Felsitic rocks of the Damwal Formation are present at surface where the Vryheid Formation has been eroded by local streams. Coal seams are strongly influenced by varied depositional environments and / or the present day erosional surfaces. The coal seams (and strata) are generally flat-lying to gently undulating with a regional dip to the south southeast. Due to the varied depositional environments (e.g. basement topography) and the present-day erosional surface, not all of the seams are present at any one locality. (GCS, 2015).

The project area is located within the Witbank Coalfield. The coalfield in the Kriel locality is underlain by a sequence of Dwyka and Middle Ecca strata which rests on an undulating floor composed of felsite’s, granites and diabase associated with pre-Karoo depositional activities. The stratigraphy throughout the Kriel area is uniform and the coal seams are generally flat and gently undulating. However, there is evidence of some dolerite intrusions that result in coal seams that are faulted or burnt along the margin areas.

Typical sedimentary sequences are present in the project target area. The No. 2 Seam, the No. 3 Seam, and the No. 4 Seam, which is subdivided into the 4-Upper and 4-Lower Seam in the area and the No. 5 Seam occurs in the area. A parting layer separates the 4-Upper and 4-Lower Seams in most cases. However, this was not evident in the drilling that took place in the area. The overburden mainly consists of sandstone with some areas including thin layers of clay in the lithology. The project area has a thin dolerite intrusion (sill) present. The sequence is underlain by the lithologies of the Dwyka Group as indicated by historical data acquired for the area.

Mining Methods

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Comminution

Crushers and Mills

Processing

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Production

Commodity	Units	2022	2021
Coal (thermal)	Mt	....	....

Personnel

Job Title	Name	Profile	Ref. Date
.......................	.......................		Jun 10, 2024