Modern Mining July 2016

COAL

and that the project was being developed to supply electricity to South Africa in terms of the cross-border procurement programme. The project calls for two or four gen- erating units, each with an output of 150 MW. It is expected that circulat- ing fluidised bed boilers will be used. Due to the fact that Botswana is a water scarce country, the project would deploy a dry cooling system. The water supply strategy includes the construction of a pipeline from the Shashe Dam, approximately 60 km from the project site, which will provide raw water to the water treatment plant and other plant and equipment as required. A nearby wellfield with 18 boreholes and sufficient capacity will provide a back-up water supply solution. A positive coal mining pre-feasibility study (PFS) by Ukwazi Mining Solutions to define the mine configuration and technical and economic potential of the Mabesekwa coal project was completed in August 2015. The coal supplied is expected to have ash content of less than 30 % and pro- duce an approximately 17 to 19 MJ/kg product which will be transported to the power plant by a conveyor system. The mine will be a conventional open pit. Shumba’s second advanced proj- ect – the Sechaba Coal Independent Power Producer (SCIPP) project – envis- ages a 300 MW coal-fired power plant being developed to supply electric- ity to Botswana and other countries in Southern Africa. At this stage Shumba Energy is the sole developer but Phumaphi told delegates to the Gaborone conference that the company was in discussions with several poten- tial strategic partners. Based on the completed conceptual design study undertaken by Parsons Brinckerhoff Power, the SCIPP power plant is envisaged to be configured as a 2 x 150 MW (gross capacity) coal- fired facility. The contracted net power available would be approximately 270 MW after deduction of auxiliary consumption. The boiler furnace will be of the cir- culating fluidised bed subcritical natural circulation type with one steam genera- tor provided for each unit, with dry air cooled condenser technology. Sulphur

Drill rig operating at the Mabesekwa project.

Oxide (SOx) control will be achieved by in-situ SOx capture by limestone dosing in the boiler furnace. Particulate matter control will be achieved with electro- static precipitators. The estimated in-situ coal resource at Sechaba is 1,14 billion tonnes, predomi- nantly contained in two main coal seams – the upper Taukome Bright Seam (TKS) and the lower Morupule Main Seam (MMS). Average seam thicknesses are 2,6 m (TKS) and 3,7 m (MMS) with the coal found at average depths of 30-100 m. As with Mabesekwa, Ukwazi has been responsible for a mining pre-feasibility study for Sechaba which was completed in 2014. The selected mine configuration targets surface and mining infrastructure and an underground mine to ramp up to 1,5 Mt/a in the shortest possible time frame and at the lowest cost. After this production level has been established, it is envisaged that a phase two expansion could increase the annual production to 3 Mt/a. Appropriately detailed mine lay- outs for the boxcut and the underground mines for MMS and TBS were prepared and major equipment sized. Summing up Shumba’s ‘offering’, Phumaphi said Botswana and the wider Southern African region offered few advanced IPP opportunities, which placed Shumba – with its two advanced projects – in a very favourable posi- tion. He said both projects had excellent infrastructure access and both enjoyed strong support from the authorities in Botswana. He concluded by saying that Shumba was hoping to be providing an initial minimum supply of 265 MW to the grid by 2020. Photos courtesy of Shumba Energy

July 2016  MODERN MINING  27