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

Small-scale mining of gemstones and semi-precious stones is widespread in almost all SADC countries, though
the mining of gemstones (diamond, emerald, sapphire, garnet and ruby) is considered to be “illegal” by most
SADC Governments because the small-scale mining operations are very often unlicensed.
The predominant semi-precious stones mined are: garnet, amethyst, aquamarine, citrine, topaz and beryl. Here
again, the major problems associated with this activity are enhanced soil erosion and increased sedimentation
of nearby watercourses, caused by inadequate control of surface spoil and waste rock heaps.
2.5.4 Tantalum and tin
There a re a few instances where small-scale miners work specific pegmatite deposits for tantalum and tin.
These two metals are relatively valuable and can be sorted manually from the surrounding rock matrix. In view
of the low numbers and small-scale of these operations, the associated impacts are negligible.
2.6 Differentiating between direct, indirect and cumulative impacts
Environmental factors (“impacts”) associated with, or caused by, mining, as distinct from those associated with
the subsequent use of the extracted minerals, are largely confined to relatively restricted areas in the vicinity of
the appropriate geological formation and downstream in the catchment where the deposit is located. These
impacts would normally be considered to be “direct” impacts that can be linked directly to the mining and ore
processing operations.
In contrast, there are many other types of impacts that are associated with mining activities, but do not occur as
a direct consequence of the mining activity itself. These would be considered to be “indirect” impacts. A typical
example would be the variety of impacts caused by the activities of individuals and organizations that take place
in areas peripheral to a mining operation. An example of this is the discharge of effluent and wastes from
households, businesses and factories in the towns that develop around or close to a particular mining operation.
In several instances, these indirect impacts can exceed the total environmental impact of the original mining
operation and thereby require a far greater degree of management attention.
The term “cumulative impacts” is generally applied to those situations where several impacts from different
processes and activities combine to exert a greater set of (usually adverse) effects than those that would be
predicted from the original activities. An example of this type of situation would be the combination of adverse
effects that a community would experience if it were exposed simultaneously to atmospheric emissions of
gases, wind blown dust and effluent discharged from a mining operation. A second example would be the
situation where effluents and discharges from several mining operations or industries in a single catchment
exerted a set of combined effects or impacts on the river system draining the basin.
In some circumstances, there may be synergistic effects, where the combined (cumulative) effect of two
different activities is greater than would be expected from a simple combination of the two isolated activities.
Similarly, there are also certain circumstances where the impacts from two different activities effectively
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