All of the known coal deposits in South Africa are hosted in sedimentary rocks of the Karoo Basin which covers approximately 60% of South Africa and is filled with units of the Karoo Supergroup.

The Karoo Supergroup is lithostratigraphically subdivided into the Dwyka, Ecca, Beaufort and Stormberg groups, succeeded by the Drakensburg Formation. The lithologies are representative of depositional environments including glacial, deep marine (including turbidite), shallow marine, deltaic, fluvial, lacustrine through to aeolian deposits. Within the Main Karoo Basin, the Karoo Supergroup as depicted in the figure below, comprises the Dwyka Formation, Ecca Group and Beaufort Group overlain in turn by the Stormberg Group and Drakensberg Group. Sediments reach 12,000 m thickness, overlain by thick flood basalts of the Drakensberg Group.

Within the Karoo Basin, 19 coalfields have been defined based on variations in sedimentation, origin, formation, distribution and quality of the coals. The coals range in age from Early Permian (Ecca Group) through to Late Triassic (Molteno Formation, Stormberg Group) and are predominantly bituminous to anthracite in rank, which is a classification in terms of metamorphism under the influence of temperature and pressure. The Gus Seam is stratigraphically located in the Vryheid Formation within the Ecca Group.

Uitkomst falls within the Utrecht Coalfield, which has a total of nine recognised coal seams which are develope ........

The current underground mining areas are extracted by two bord-and-pillar conventional drill and blast sections, one single header and one double header. The combined mining rate for both sections are planned at 45 ktpm. Each production section consists of a coal cutter, electric drills, battery scoops, feeder breaker and section belt. The mining activities are conducted by a mining contractor.

The pillar sizes are determined by using Munro/Madden drill and blast safety factors. A weak roof area was identified within the southern extent of the mining area. The current methodology is to exclude the majority out of the life of mine plan, and only to develop through the area. Within the weak roof area, the coal loss is increased to 4 cm.

The ventilation of the underground workings is via surface fans, ventilation brattices are utilised to closeoff mined-out areas and direct sufficient airflow towards the mining sections. In-section ventilation of production headings are conducted with a 90 kW section fan. Sufficient airflow is maintained by closing off mined-out areas to reduce the overall resistance as mining distances increases. The current ventilation is sufficient for the next 18 months whereby the ventilation would require upgrading.

The modifying factors applied to the mineable resource included an average geological yield of 88.5%, the average contamination for the life of mine applied was 4.8% for dilution and 5.1% for brushing. The dilut ........

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