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

Water quality changes are widely considered to be the most significant consequence of mining activities. This is
partly because of the wide variety of undesirable contaminants that are derived from mining operations, and
partly due to the frequency and persistence of these problems. Historical records of mining activities in the
sixteenth century clearly demonstrate the strongly antagonistic public opinion regarding the adverse effects of
mining on water quality (Agricola, 1556, cited in Environment Canada, 1996). In many areas, varying degrees
of adverse public opinion of mining activities continues to the present day (Viljoen & Reimold, 1999; Chenje,
2000).
Most mining operations share similar sets of activities or materials that generate contaminants and lead to
pollution of surface water resources. The following mining sources generate a diversity of contaminants that
have been shown to have adverse effects of varying intensity on surface waters, groundwater, aquatic plants,
surface water biota and submerged sediments (Pulles et al., 1996):
• Underground stopes;
• Surface rock and sand dumps;
• Slimes dams and delivery pipelines;
• Coal discard dumps;
• Coal fines;
• Rehabilitated opencast pits;
• Plant areas; and
• Explosives residues
Chemical contaminants in mine water systems are very varied and complex in nature. Often, these
contaminants have synergistic effects on a variety of different environmental components and these can seldom
be reduced or ameliorated. Pulles et al., (1996) indicate that South African coal and gold mines have been
unable to cost-effectively eliminate the following sources of water pollution:
• Acidic saline conditions with mobilized dissolved metals and nutrient enrichment caused by pyrite oxidation
and blasting residues;
• Eutrophication, pH fluctuations and decreased oxygen content caused by sewerage discharges; and
• Cyanide and radionuclide contamination of gold mine seepage water.
These problems are not unique to South Africa and are shared by every SADC country, as well as most mining
operations worldwide.
2.3.4.4 Landscape-scale ecological changes
The process of constructing, erecting and commissioning new mining infrastructure often results in large-scale
alteration of the environment, particularly at landscape and ecosystem levels. Infrastructure associated with
mine construction includes transport and service corridors (railway lines, roads, pipelines, conveyers, airstrips,
port facilities, power, water and gas corridors) and surface facilities (e.g. offices, laboratories, workshops,
vehicle parks and service bays, fuel storage and dispensing depots and warehouses), sinking of mine shafts
and the removal of soil, vegetation and rock to access ore deposits and create sites for tailings and waste
disposal areas. The landscape level environmental impacts are generally in the form of landscape alteration
and fragmentation or dispersal of biological habitats, populations, communities and ecosystems. They also
include altered patterns of stream flows, especially where mines have to be de-watered.
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