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

Sanyati, all may well contribute or have contributed acidity and heavy metals such as nickel, lead, copper,
cobalt and zinc to the local rivers. Copper Queen and Sanyati are located on highly vulnerable shallow, sandy
soils. There was also a small mercury mine at Richmond, near to the Munyati River, where the main railway
line crosses it.
Further high impact is to be expected from the three chrome smelters located in the sub-catchment, as well as
the nickel smelter at Empress and the blast furnaces at Redcliff. Hexavalent chromium is associated with
effluent from chrome smelters. The ZISCO and ZIMASCO smelters in the Kwekwe area are very close to the
Sebakwe River, a major perennial tributary. The Empress smelter is in close proximity to the Munyati River
itself.
There is extensive alluvial gold mining from the Midlands Greenstone Belt downstream and small-scale chrome
mining along the Great Dyke (Figure 3.14).
Examination of the water quality data presented above shows elevated levels of total dissolved and suspended
solids, total hardness, nitrates, phosphates and iron. The sites that figure most prominently in terms of values in
excess of the “blue” limits are all located in the Kwekwe area46. This could be related to the very dense
concentration of gold, antimony and iron producing mines, current and historical, in the Kwekwe area, as well as
the Kwekwe smelter. However, the impact of the Kwekwe urban area cannot be discounted in this
consideration, and commercial farming is quite likely to be the source of nitrates and phosphates.
The Sanyati – Munyati Sub-catchment is the most heavily mined area in the country, both currently and
historically. The impact of mining is concentrated in the Midlands Greenstone Belt and the series of heavy
metal producers in the lower Munyati and Sanyati valleys. The impact of the Midlands Greenstone Belt is
accentuated by the fact that all the major rivers in the sub-catchment flow through it.
Extensive exploration continues, notably for gold and base metals. It is therefore indicated that the impact of
mining on this sub catchments is not likely to decrease in the foreseeable future.
3.30 The Mupfure sub-catchment
3.30.1 General description
3.30.1.1 Hydrology
46 Sites CR62,63,64 and 65
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