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

The two lone water quality data points lie in an area of historical gold mining, and it is possible that this activity
may relate to the elevated levels of total dissolved and suspended solids and sodium reported in the diagrams
above. However, it is more likely that this effect arises from the impact of the City of Bulawayo, some few
kilometres upstream.
Mining and minerals processing operations in the sub-catchment that have high potential impact fall into groups:
• Various gold mines in the Bubi Greenstone Belt, which might contribute arsenic and acid mine drainage;
• Shangani mine, which might contribute acid mine drainage and metals such as nickel, copper and cobalt;
• Pilgrim mine in the Bubi Greenstone Belt, now closed, may still contribute mercury contamination
• Gothic mine in the Lower Gweru Greenstone Belt, which may contribute acid mine drainage and metals
such as nickel, copper and cobalt antimony
• Alluvial gold mining in the Upper Gwayi River and its tributaries
• Lead and tin mining in the Kamativi-Dete Inlier
• The Kamativi tin smelter, now defunct
The larger gold, tin and nickel mines all have large waste rock and tailing dumps.
Thus it can be seen that the major impact of mining operations in the sub-catchment is likely to come from the
Greenstone Belts that lie in the headwaters of the Gwayi and its tributaries. Such impact as they have is
therefore likely to be felt to some extent, throughout the river system, although dilution will have an effect over
distance. There is no significant impact of mining in the Lupane – Nkayi (central) areas, but mining once again
has a potential impact on the river system in the Kamativi area, where shallow soils increase water system
vulnerability.
3.26 The Sebungwe and Lwizilukulu sub-catchments
3.26.1 General description
3.26.1.1 Hydrology
This is Zones Z2 and R of Area A (ZSG, 1984). The area comprises a series of small sub-catchments, whose
rivers flow from the Chizarira Plateau into Lake Kariba. The largest of these rivers are the Mlibizi, Sebungwe
and Lwizilukulu (Rwizi Ruhuru). None are perennial (Figure 3.2). There is a small wetland associated with the
Chibwatata Hot Springs, near Binga Town.
3.26.1.2 Geology
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