Local coal-mining company Anglo Coal is implementing a
R296,3-million project in South Africa’s main coal-producing
region, the Witbank Coalfields, in Mpumalanga, that will iron ore in austriaenable it
to offset the costs of treating polluted mine water.
The executive board of Anglo Coal’s parent company, Anglo
American, approved the Emalahleni water-reclamation project in
September last year. The project will treat 20 Ml/day of water that
originates from Anglo Coal’s Kleinkopje and Green-side
coal-mines and, ultimately, the Landau colliery.
BHP Billiton coal-mining subsidiary Ingwe, which also has mining
operations in the area, could potentially buy into the
project.
Anglo Coal Environ-mental Services senior project manager Peter
Gunther says that the project will treat the water to SABS 241
Class 0 drinking water, which will be sold to the local
municipality to offset the costs of the project.
The Emalahleni water-reclamation project will assist the region to
tackle two of the most serious environ- mental challenges that it
is faced with – the problem of widespread water pollution by
acid-mine drainage and the forecast shortage of water to meet the
needs of its growing population in future.
Gunther says that, while the local mines all produce excess mine
water that will increase beyond their closure, the Olifants river
catchment area, which intersects the Wibank coalfields, has a
deficit of 192-million m3/y of water. Regional mine-water treatment
projects will tackle water pollution by acid-mine drainage and
assist the local authorities of Emalahleni (Witbank) and Steve
Tshwete (Middelburg) to supplement their water resources.
It is estimated that the water requirements of the Emalahleni local
authority, which is currently 77,3 Ml/d or 28,2-million m3/y will
increase to 121 Ml/d or 44,4-mil- lion m3/y by 2015, and 182 Ml/d
or 66,5-million m3/y by 2030.
Water consumption in the Steve Tshwete local authority is expected
to grow from the current 31 Ml/d or 11,57-million m3/y to 50 Ml/d
or 18,32-million m3/y by 2030.
It is anticipated that a regional water company will be established
to manage the distribution of the water treated by the Emalahleni
waterreclamation project for reuse by the mines, allocation to new
mines, supply to the local authorities of Emalahleni and a similar
project will deliver water to Steve Tshwete.Anglo Coal has proved
the efficacy of the technology that it will use to reclaim mine
water in the project area in a demonstration plant.
A demonstration plant (a replicate of the full process of the main
20-Ml/day Emalahleni plant) was commissioned in September 2005 and
treated 120 m3/d of water for three months. The treatment process
boosted the pH levels of the water from 2,9 to between 6,5 and 7,5,
reduced the total dissolved solids count from as high as 4 500 to
135 mg/l and decreased the sulphate content from 3 500 mg/l to 80
mg/l. The Emalahleni water-reclamation pro-ject is expected to be
operational by mid-2007.