Sigma-Mooikraal colliery

 mine shaft, coal mine

Sigma-Mooikraal colliery is owned by Sasol and provides coal to Sasol Infrachem Industries (SII) in Sasolburg. Adits access the coal seams from the side of the boxcut and coal is shipped to SII over an 18km long conveyor. The coal conveyed is used to raise process steam and as fuel for the generation of electricity for Infrachem, whose chemical products ceased being made from coal when the feedstock was switched to natural gas and the coal-fired gasifiers were shut down. Now coal-consuming activities are required only for steam and power generation. The mine is capable of producing two-million tons of coal a year and the coal is crushed to a size <20 mm.

Unlike the Sasol mines in the Secunda area, productivity is lower in the Sasolburg area due to challenging geology which requires 5 times more roof support. Production is carried out using the conventional bord-and-pillar method, continuous miners (CMs) and shuttlecars. Bolting is done by new-generation Fletcher roof-bolting machines.