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

Table 5.16: Representative water quality data for the Great and Middle Letaba rivers, as well as the Nsama,
Thabina, Klein Letaba and Letsitele rivers. [All data are given as mg/litre, except pH (log units) and electrical
conductivity (mS/metre)].
Parameter
G. Letaba
(Tzaneen)
G. Letaba
(KNP)
M. Letaba K. Letaba Thabina Letsitele Nsama
pH 6.4 7.45 7.3 7.4 7.6 7.3 7.7
Conductivity 4.0 21.4 20.6 28.6 26.1 19.5 32
TDS 37 165 162 219 221 162 248
Ca 2 14 18 18 28 20 21
Mg 1 7 8 14 12 7 14
Na 4 18 9 17 9 11 23
K 1.2 4.2 4.5 2.8 0.8 2.1 4.4
Si 6.4 7.3 5.8 14.8 9.9 8.9 11.1
Total Alkal. 11 71 89 108 122 75 123
Cl 4 23 5 11 6 13 15
F 0 0.1 0.2 0.1 0.2 0.1 0.2
SO4 4 5 4 9 7 5 8
Fe 0.57 1.58 0.19 0.38 0.93 0.19 0.41
Mn 0.05 0.22 0.06 0.04 0.26 0.06 0.10
These data demonstrate that the general water quality in the Great and Middle Letaba rivers and their main
tributaries is generally good. The declining water quality along the length of the Great Letaba River probably
reflects a combination of evaporative concentration and irrigation return flows.
5.8.6 Implications for water quality and quantity management
The available evidence suggests that there is little evidence of any adverse effects that could be attributed to
mining activities. However, given the alluvial mining activities in the Nsama River, it would be prudent to
examine the water quality of this tributary more closely.
The other mining and quarrying activities in the upper reaches of the Middle Letaba River would be likely to
increase suspended sediment levels.
5.9 The Shingwedzi sub-catchment
5.9.1 General description
5.9.1.1 Hydrology
This sub-catchment consists of the area drained by the Shingwedzi River and its major tributaries, the
Phugwane, Mphongolo and Shisha rivers in South Africa, as well as the slightly smaller Mozambican portion
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