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

Mechanical weathering processes dominate in arid areas with low rainfall and high evaporation rates, causing the
fragmentation of primary minerals such as quartz into smaller fragments and soils are predominantly sandy.
Conversely, in warm, humid and wet landscapes chemical weathering processes dominate soil formation, giving
rise to extensive deposits of secondary clay minerals. In zones where intermediate rainfall and evaporation values
are recorded, both mechanical and chemical weathering processes are equally important. Mechanical weathering
processes increase in importance as the rainfall declines and chemical weathering processes decrease in
importance as determinants of soil formation.
Mines located in areas where Weinert N values are less than 2.00 usually show distinctive contributions to water
quality and often require concerted management attention to prevent, minimize and/or remediate problems
related to “water pollution”. Conversely, mines located in areas where Weinert N values are substantially
greater than 5.00 usually show little or no contribution to local water quality and often allow mine management
considerable leeway in their “pollution control” efforts.
2.8 Legislative requirements for the control and management of impacts
attributable to mining operations in southern Africa
In southern Africa, the respective Constitutions of the different SADC countries provide the foundation for
legislation to control environmental impacts by promoting the rights of all people to a "safe and healthy
environment". Despite minor differences between the legislation in the different countries, the basic intentions are
very similar.
Currently, most countries still have several old and new sets of interlocking legislation that exert control over
mining and related activities and their impacts on the environment. Many of these acts are now in the process of
revision to reflect more clearly the principles embodied in their respective constitutions and the tenets of
international treaties designed to minimize environmental degradation. Inevitably, the changes in existing
legislative frameworks in each country are complicated by the fact that some pieces of legislation can be
interpreted in ways which appear to conflict with the terms and conditions set out in other legislation. Similarly,
there are situations where legislative requirements in neighbouring countries differ from each other, thereby
complicating the process of managing impacts on shared resources (e.g. shared river basins). Nevertheless,
despite these differences, the legislative framework in each country seeks to promote the economic benefits to be
gained from mining whilst reducing to a minimum the risks to human safety and the adverse consequences of
environmental degradation. From an environmental perspective, most attention is focused on minimization of
waste products and associated sources of pollution or contamination, and the rehabilitation of land surfaces that
have previously been mined or used for the disposal of waste products (Wells et al., 1996; Gurney et al., 1996;
Chenje, 2000; SADC-MSCU, 2001).
Clearly, this attention to minimizing the adverse consequences of mining activities is a welcome development. In
this context, it is also clear that many older mining operations started at a time when there was little or no explicit
concern for the surrounding environment. Disposal of wastes was carried out in a manner designed solely to
minimize costs, rather than to prevent pollution or facilitate rehabilitation. In many instances, old mines were
simply abandoned and no attempt was required (or made) to rehabilitate the surface workings when the economic
life of the ore body was exhausted. This situation now places enormous responsibility for rehabilitation on the
respective governments, and is accompanied by a considerable economic burden (Fuggle & Rabie, 1996; Chenje,
2000).
In some SADC countries, however, certain pieces of legislation that cover air and water pollution are poorly
enforced as a result of both weak institutional arrangements and inadequate or incomplete provisions in legislation.
Chenje (2000) cites Zimbabwe’s Atmospheric Pollution Act of 1971 as being a case in point, where industries that
existed prior to promulgation of the legislation are allowed to continue using outdated equipment and need not
upgrade their facilities.
In contrast, Zambia’s Air Emission Control Regulation Statutory Instrument No. 141 of 1996 is stronger and sets
out emission limits for sulphur dioxide, dust and heavy metals, but ignores the problems of greenhouse gases
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