Integrated chemicals company Sasol forecasts it will complete the 10.5-million-ton-a-year Impumelelo colliery – formerly known as the Brandspruit mine – replacement project by June next year.

The project involves the construction of a new 8.5-million-ton-a-year coal mine, which is upgradeable to 10.5-million tons a year.

The No 4 and No 2 coal seams will be mined simultaneously at the project, with the thinner and more complex No 2 seam lying below the No 4 seam. The final shaft depth will be about 225 m below the surface.

The project includes the development of service, ventilation and decline shafts, materials handling systems (including a 28 km overland conveyor, surface surge bunkers, underground conveyors and surge bins) and all the mine infrastructure needed to support operations.

The 11.7-m-diameter men-and-materials shaft will be 210 m deep, with a four-sided station on the No 4 seam.

The 6.7-m-diameter ventilation shaft will also be sunk to 210 m, with access through the four-sided station to the coal production sections.

The shaft complex has been designed to operate for a minimum period of 35 years.

The conveyor system will deliver coal to the Synfuels complex, becoming the longest conveyer system of its kind in the southern hemisphere.

The project is part of Sasol’s capital replacement project involving four coal projects in Mpumalanga, which all service Sasol’s Synfuels plant, in Secunda, and will be the last of the four mines to be completed.

Meanwhile, in July, Sasol officially inaugurated its new Shondoni colliery in Mpumalanga as part of its R15-billion mine replacement programme.

Meaning “a place of wealth”, Shondoni replaces Sasol Mining’s Middelbult colliery, which has reached the end of its life span.

Sasol Mining is South Africa’s third largest coal producer and runs one of the world’s largest underground coal-mining complexes. It produces over 40-million tons of coal yearly, of which more than 90% is used as critical feedstock for the production of Sasol’s high-quality synthetic fuels and a range of chemicals.

Sasol joint president and CEO Bongani Nqwababa said the R14-billion mine replacement programme supports Sasol’s strategy to operate its Southern African facilities until 2050. The programme commenced in 2009.

“It is also part of our capital expenditure in South Africa which, over the last five years, has amounted to more than R94-billion,” said Nqwababa.

Modern in many respects, distinguishing Shondoni from the rest of Sasol’s other five collieries is the use of renewable energy, which includes the use of solar geysers to heat pumps. The mine also holds the record of having the longest single flight conveyor without an intermediate booster drive in Africa, at 21 km. Over the next 30 years, it is expected to deliver between 8-million and 9-million tons a year of coal and currently employs about 1 200 people.

Further, the Syferfontein opencast operation has in part been replaced by the Tweedraai 2.5-million-ton-a-year project. Syferfontein, however, is dwarfed by the 10.5-million-ton-a-year Thubelisha shaft at the Twistdraai colliery which will extend operations well into 2040.

The Thubelisha shaft, situated in the northeast of the Secunda complex, will supply coal to Sasol Synfuels, and the export and domestic market. The current Twistdraai Colliery shaft system has reached its economic limit and requires relocation of the shafts to the Thubelisha shaft.

Twistdraai, located towards the east of the Secunda coal deposit, works permian seams of the Vryheid Formation. The No 3 and No 4 lower seams converge into a single unit within the Twistdraai reserve area, forming the feedstock for the beneficiation process to produce a low-ash product.

Mines built in the 1980s were no longer viable and needed to be replaced with bigger, better and bolder mines. Sasol thus committed R15-billion to the coal replacement project which was initiated to replace about 60% of its operations which were nearing or have met the end of their economical lives.

These mines are set to maintain the required coal mining production of over 40-million tons a year needed to sustain the Synfuels complex.