OVERVIEW OF THE IMPACT OF MINING ON THE ... - IIED pubs

There are currently no legal exploration activities taking place.
3.27.3 Alluvial mining
Neither known nor likely.
3.27.4 Monitoring systems
3.27.5 Water quality data
None.
None available from ZINWA. The following data covers actual discharge from Sengwa Colliery (Table 3.28).
Table 3.28: Actual discharge from Sengwa Colliery, after Chenje et al. (1998).
pH 7.6 Fe 0.3ppm Fe SO4 2-
Alkalinity 169ppm Cl -
NO3 -
0.39ppm N
3ppm SO4 2-
3.27.6 Implications for water quality and quantity management
clxvi
10ppm Total hardness 160ppm
10ppm Ca 53ppm
The only significant mining operation in the sub-catchment was the Sengwa Colliery, now closed. It is to be
expected that the colliery may have contributed acid mine drainage, sulphates and iron to the river system,
especially given its adjacency to the Sengwa River. However, the limited data from Chenje et al. (1998)
suggest that the problem may not be very severe. There is also the potential for fluorine contamination from
associated Upper Karoo sediments (cf. Magalela, 1997).
An option frequently discussed in the feasibility studies and environmental impact assessment for the colliery
was the rerouting of the Sengwa River away from the colliery through an old river channel, a few kilometres to
the west. Were this option to be undertaken sometime in the future, during a putative reopening of the colliery,
it is probable that the impact of the colliery itself would be reduced. Impact on the river system would thus be
the diversion itself, as well as the exposure of the river water to lithologies such as burnt coal measures.