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 developed to varying extents across the coalfield. At Uitkomst, only two seams are developed, namely the Alfred and Gus Seams. The Gus Seam is however the only seam of economic importance at Uitkomst Colliery, this due to the Alfred Seam being poorly developed and sporadic or too thin for economic extraction on the Uitkomst property.

The Gus Seam comprises banded bright, dull and lustrous coal in varying proportions with the lower portion of the seam invariably being of better quality than the upper part. The seam usually contains one or more fine- to medium-grained sandstone partings towards the top which may be up to 20 cm in thickness. The seam thickness varies between 0.8 cm and 1.9 m in a north-south trending zone in the central area of the mining lease area. To the south, the seam outcrops into the Dorpspruit and Kweekspruit Valleys. The seam extends north under the escarpment where the depth of seam is approximately 300 m below surface. The seam depth rapidly increases to the north to approximately 800 m below surface.

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 dilution consisted of 2 cm from the roof and floor for normal working conditions and 6 cm in the roof for weak roof encountered. Brushing is required to increase the excavations for the conveyor belt and traveling way (2.2 m high) and intersections and transfer areas (2.6 m high). A 7.0% increase in tonnage was the result of the inclusion of superficial moisture.

The plant consists of a dual stage roller crushing circuit followed by coarse (10 to 40 mm), middlings (1 to 10 mm) dense medium cyclone washing circuits with the fines (-1 mm) material upgraded in a fines spirals circuit. Equipment is generally in good condition with the plant being structurally sound. The plant is run mainly on grid power with make-up water sourced from nearby farm dams and potable water from boreholes.