ROBUST LIFE EXPECTANCY The Mabesekwa mine's coal reserves are forecast to last well over 50 years
Photo by: Duane Daws
The Mabesekwa coal mine, in Botswana, is at an advanced stage of the Mabesekwa export independent power producer (MEIPP) project and will seek to secure its mining licence and agreements to supply electricity to the South African Coal Baseload IPP programme and the domestic Botswana Greenfield Coal Baseload programme, geological consulting services provider Gemecs tells Mining Weekly.
The mine, owned by Botswana enterprise exploration company Shumba Energy, is part of the MEIPP and will supply the 300 MW Mabesekwa IPP power plant with enough coal to sell its electricity in the Southern Africa region for the entire life of the power plant, which is in excess of 20 years.
“Normally, the life of a power plant is at least 20 years, but there are coal reserves to last well over 50 years at the Mabesekwa coal mine,” Gemecs director and consulting geologist Nico Denner points out.
As such, the coal produced at the Mabesekwa mine will not be exported and most, if not all, of the coal mined will be used to produce electricity at the IPP plant.
The mine received environmental approval from the government of Botswana in July. The coal seam can be up to 18 m thick, with an in situ resource of around 844-million tons of coal. Currently, at least 175-million tons of coal can be mined from an opencast operation, with substantial underground resources areas available.
Denner points out that geology in the area is similar to that of South Africa, with the only key difference being the thickness of the seam.
Because the seam is thicker than the standard coal seams, selecting the best mining method and the location of the best-quality coal for mining is challenging, says Denner. This is where Gemecs becomes involved, defining the structural and coal quality mining blocks, as well as selective mining horizons for optimum-quality coal for mining, through the use of geological modelling using Geovia Minex software.
Therefore, geological models need to define the zone within the coal package that will ensure that the project is sustainable and supplies the best possible coal to enable optimal power plant performance.
Using selective mining can enhance the quality of the coal, Denner says, adding that this will result in less of the resource being mined and the extraction of higher-quality coal that does not require much washing. “Thus, higher-quality coal is supplied to the power station, which can improve its efficiencies,” Denner points out.
The Mabesekwa mine will initially be an opencast mine and will eventually be developed into an underground operation, he adds.
Besides completing the resource model for the Mabesekwa mine in 2015, Gemecs has also completed the model for the Mbeya coal-to-power project, owned by mineral explorer and developer Kibo Mining, in Tanzania. The Mbeya coal mine will supply coal to a 300 MW mine-mouth thermal power plant that will provide power for Tanzania in anticipation of the country’s power generation requirements.
Mbeya has a coal resource of 109-million tons, with 71-million in the indicated category and 38-million in the inferred category, according to Kibo’s website. As with Mabesekwa, the life of Mbeya is expected to outlast that of its power station.
Denner concludes that, when the Mabesekwa and Mbeya mines start operations, Gemecs will define and keep the geological models up to date with any new information as part of the ongoing exploration programmes, which includes finding adequate coal resources going forward.