Mine Closure - Mining and the Environment: From Ore to Metal - page 822

In assessing the success of rehabilitation, the diversity of plant species is not particularly
important in the i rst few years. What is important is that the number of species increases
from one year to the next. The same applies to fauna. Some insect species will rapidly col-
onize even newly established vegetation, particularly if natural vegetation occurs nearby.
However, it will be many years before the faunal community on reclaimed sites will be
comparable with undisturbed natural areas. Again, the important thing to establish is
whether or not there is a trend toward increasing diversity.

The important thing to establish
is whether or not there is a trend
toward increasing diversity.

Culturally Important Plants

Indigenous Peoples throughout the world have used specii c plants for a variety of pur-
poses including sustenance, medicines, decoration and ritual observances. Tropical forests,
in particular, contain many plant species that are used by the local Indigenous Peoples.
Where mining takes place in these situations, it is important that culturally important
plants are included in the rehabilitation programmes. To this end, an ethno-botanical
survey is undertaken as part of the original baseline study. From this study, a list of cul-
turally important species is compiled with details of the nature and occurrence of each.
Depending on the species, seed can then be harvested or, in some cases seedlings can be
removed from areas to be mined and transplanted, for use in rehabilitation.

Progressive Rehabilitation versus Post-Closure Rehabilitation

Strip mining for coal, shallow open Pit mining for bauxite and 'bottom-up' waste rock
dumping practices all provide the opportunity for progressive rehabilitation, rather than
waiting until mine closure. There are several signii cant advantages to progressive reha-
bilitation, including:
●

Alternative practices and treatments can be tried and compared, with experience
gained from each rehabilitated area leading to improvements in subsequent efforts;

Alternative practices and
treatments can be tried and
compared, with experience
gained from each rehabilitated
area leading to improvements in
subsequent efforts.

●

Unsatisfactory results can be identii ed and readily rectii ed;

●

Topsoil can be used immediately, rather than after a period of stockpiling, with the
result that more of the contained seeds and micro-organisms will be viable.

●

In many cases - such as where Vetiver Grass is used - newly rehabilitated areas may
provide propagules for subsequent rehabilitation;

●

The full complement of mine staff and equipment are available to be involved in both
implementation and evaluation of rehabilitation efforts and in any supplementary
treatments;

●

In the case of 'bottom-up' waste rock dump rehabilitation, vegetation on the lower
benches assists in erosion control;

●

Less funds need to be accumulated for closure, and

●

Once successful results have been achieved, costs for the balance of areas to be rehabili-
tated after closure can be estimated with coni dence.

There is usually no potential for progressive rehabilitation of tailings storages, except
where multiple cells are i lled sequentially. Accordingly, tailings rehabilitation may be the
major task remaining following mine closure. Filtration of tailings to produce i lter cake,
promises to offer considerably more options in tailings management, including the possi-
bility of progressive rehabilitation.