Environmental Engineering Reference
In-Depth Information
21
Mine Closure
It is Not Over When it is Over
Mine closure, the subject matter of this chapter, is the term applied to the
activities undertaken after completion of mining and mineral processing. It includes
decommissioning, dismantling and removal of plant and equipment, and the
rehabilitation of areas disturbed by mining and associated activities. Rehabilitation
and reclamation are the most commonly used terms for the procedures and
practices applied to return land disturbed by mining to a functional condition.
Rehabilitation is the term most commonly used in the Australian mining industry,
while reclamation is the term favoured in the USA. The terms are essentially
interchangeable, but the term rehabilitation is used throughout this topic.
Revegetation is another commonly used term, its meaning being confi ned to
that part of the rehabilitation process involving establishment and maintenance
of plants. Restoration is a more specifi c term which refers to rehabilitation that
returns the land surface to its pre-existing function and condition.
Many environmentalists object to use of the term 'restoration', arguing that mining causes
such drastic changes to the landscape, soils, habitats and hydrologic conditions, that it is
impossible to re-establish pre-existing conditions. This negative view-point is not sup-
ported by the evidence. In the relatively short period since the advent of environmental
awareness in the mining industry in the 1970s, there have been many examples of success-
ful restoration in the functionality and productivity of agricultural lands, including range-
lands and a variety of annual and perennial cropland systems. Substantial progress has also
been made in the restoration of natural ecosystems; however, the time required for natural
succession means that many areas rehabilitated with native vegetation, do not yet match
the condition of adjacent unmined areas in terms of biodiversity and habitat diversity. On
the other hand, evidence of natural succession and progressively increasing biodiversity
indicate that full restoration will be achieved in time.
There are also many situations where mining takes place in areas that are relatively bar-
ren and depauperate in biota due to natural infertility, physical impediments or a prior
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