Mine Closure - Mining and the Environment: From Ore to Metal - page 805

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Contingencies; and

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Inl ation.

Contingency costs are necessary to address the errors that exist in every cost estimate that
is based on assumptions and conceptual information rather than actual data.
Finally, while they may be considered separately, 'social' costs related to redundancy
payments or contributions toward future maintenance and operation of social assets also
need consideration and funding.

21.4 REHABILITATION

Rehabilitation and revegetation planning is an essential element of mine closure planning,
and commences at the mine planning stage. As far as possible, the mine operator aims to
progress rehabilitation in parallel with mining. In open cast mining, rehabilitation follows as
mining progresses, and i nal rehabilitation efforts at the end of mine life are minimal. The
post-mining land use for the mine area, and hence rehabilitation and revegetation should
be agreed upon with local government, traditional landowners, and other interested parties
from the beginning. This can be a challenging process since opinions on post-closure land
use differ. The central government, for example, may insist on reinstalling native vegetation,
while the local government may favour productive agricultural use.
The primary focus of post-closure activities is monitoring the progress of required
activities, and when necessary providing additional management inputs until landform,
vegetation, water quality and social infrastructure meet agreed targets, or until manage-
ment of the former mining area is integrated into existing local or regional management
systems.
A check-list of issues, relevant rehabilitation objectives and rehabilitation measures that
apply to each component of a mining operation is provided in Table 21.3 , which has been
reproduced from Khanna (2000).
Mine closure measures aim to leave a stable and productive post-mining environment
behind. Post-closure activities provide additional management efforts until landform, veg-
etation, water quality and social infrastructure are self-sustaining and meet the require-
ments of their users, or until management is integrated into the management of the
surrounding area.

Mine closure measures aim to
leave a stable and productive
post-mining environment behind.

Ultimate Land Use and Design of Final Landform

Selection of the ultimate land use, and related to it, the i nal landform is an important ini-
tial step in rehabilitation planning. In the USA, it is a commonly stated requirement that
the ultimate land use should be of the same or higher value than that which existed prior
to mining. This presupposes a hierarchy of land use values such as the following, in order
of increasing value:
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Selection of the ultimate land
use, and related to it, the fi nal
landform is an important initial
step in rehabilitation planning.

Unused land, unsuitable for any type of farming;

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Range land - natural;

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Range land - improved pasture;

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Crop land;

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Land used for intensive agriculture; and

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Residential/commercial/industrial land.