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

• Alluvial mining of gold in the Mazowe River and many of its tributaries;
• Several large and arseniferous gold mines in the Harare-Bindura-Shamva50 Greenstone Belt, with possible
associated acid mine drainage;
• Two large nickel-cobalt producing mines near Bindura, and the associated Trojan smelter, with acid mine
drainage and heavy metal release: data from Chenje and others (1998) suggests that nitrate contamination
may also be a problem; and
• Iron Duke pyrite mine, with possible acid mine drainage.
Gratwicke’s (1999) study shows serious acidity and salinization problems associated with Iron Duke Mine, but
also shows that these are limited beyond the confluence of the Yellow Jacket River (which drains the Iron Duke
Mine area) and the Mazowe river. Furthermore, recent dump rehabilitation at iron Duke should have improved
the situation.
Widespread quarrying of dolerite (“black granite”) alters local drainage patterns and provides depressions for
development of stagnant pools of water.
The Mazowe Sub-catchment contains several of Zimbabwe’s largest current mining operations as well as some
of the greatest concentrations of alluvial gold mining. The sub-catchment is also densely populated and a major
grain producer. The sub-catchment thus definitely deserves further study, especially given the continuation of
exploration activities in the area.
3.38 The Ruenya sub-catchment
3.38.1 General description
3.38.1.1 Hydrology
This is Zones R1-R6 of Area D (ZSG, 1984). The main tributaries of the Ruenya (Luenha) River are the
Nyangadzi (Zone R4) and the Nyangombe (Zones R5 and R6). The Mudzi River (Zone R1) flows into the
Ruenya in Mozambique (Figure 3.2).
3.38.1.2 Geology
See Figure 3.6 (ZGS, 1999). The Zimbabwe Craton underlies most of the sub-catchment: the Makaha
Greenstone Belt and granitic terrain. Zambezi Mobile Belt gneisses underlie the far north. The granites are
50 Arsenic contamination has been a major problem associated with mining in the Shamva area fro quite some
time (Stidolph, 1977)
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