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

In Mozambique, the Mozambican Department of Water Affairs monitors flows in the Olifants River downstream
of the confluence of the Olifants and Shingwedzi rivers as part of its regulation of irrigation water to the Chokwe
irrigation Scheme.
5.11.5 Water quality data
No water quality data are available for this sub-catchment.
5.11.6 Implications for water quality and quantity management
The complete absence of any information on possible mining activities in this sub-catchment prevents
conclusions being drawn.
5.12 Summary of impacts of mining operations on water resources of the Olifants
basin
The wide variety of mining operations and mineral processing activities located within the Olifants basin have
differing degrees of impact on both the water resources available to other users and on the water quality of
these resources. From the available data, it seems clear that those mining operations that are located within
low rainfall regions of the basin (predominantly the north-eastern and eastern regions, where physical
weathering processes dominate) have relatively low and/or localized impacts on the water resources. In
contrast, mining operations located in the wetter regions of the basin (predominantly the southern regions,
where chemical weathering processes prevail) tend to have far more extensive impacts. This seems to be due
to the presence of ample moisture within the soil profile that enables continual chemical changes to take place
and allows the water available to mobilize and transport the different contaminants that become available.
A summarized overview of the actual and anticipated impacts of mining operations and mineral processing
plants in each sub-catchment of the Olifants basin is given in Table 5.17. This information provides a useful
impression that could be used to focus water resource management plans and water quality management plans
in the different component areas of the Olifants basin.
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