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

Extensive alluvial mining of gold takes place in the Angwa River (Figure 3.14; Chiyanike, 1997). Some of this is
in the form of formalised claims through the Mining Commissioner, whilst the remainder is the work of smallscale
panners, whose operations falls under Special Grants held by the Rural District Councils.
3.33.4 Monitoring systems
ZINWA has a number of monitoring stations in the sub-catchment.
3.33.5 Water quality data
Water quality data is available from ZINWA for several monitoring stations in this sub-catchment (Figure 3.3).
3.33.6 Implications for water quality and quantity management
Impact is expected from four sources:
• Historical copper mining operations, possibly contributing heavy metals and acid mine drainage;
• The Alaska copper smelter, which might contribute a similar impact;
• Alluvial gold mining in the Angwa River; and
• Impact of the numerous small-scale pegmatite workings (tungsten, tantalum, kyanite, mica, among others)
in the country around Mwami.
The alluvial workings have a particularly high impact in the Angwa valley, since, prior to the arrival of panners,
the valley was largely unsettled. Informal settlements developed by the panners have led to extensive
deforestation in a previously pristine area.
Examination of the water quality data shows that total suspended solids, sulphate, fluoride and iron are elevated
(though sulphate and fluoride are still within the “blue” limits) in the Angwa River after it receives drainage from
the vicinity of the Alaska smelter. It is thus possible that the smelter is responsible for these elevations,
although recent and current housing developments in the same area could also be responsible.
The Mwami River shows elevated levels of total suspended solids, chloride and magnesium: although only the
first mentioned of these is outside the “blue” limits.
3.34 The Manyame sub-catchment
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