'n Strategie vir die rehabilitasie van versteurde mynbougebiede in Suidelike Afrika
Abstract
A STRATEGY FOR THE REHABILITATION OF AREAS IN SOUTHERN
AFRICA DISTURBED BY MINING ACTIVITIES
A literature study revealed that revegetation (grassing) of
areas disturbed by mining activities already occurred during
the early thirties. Most of the relevant research has been
conducted abroad. In the RSA, all the initial work was done
on gold mine sand dumps.
Although other methods to stabilize the dust generating dumps
had also been applied, it was finally agreed upon that a
proper vegetation cover is the only permanent solution.
During previous years, all initial revegetation attempts were
voluntary. During the fifties, law enforcement became applicable
in most countries, forcing all mines to revegetate
areas disturbed by their activities.
In the RSA several laws have already existed since 1956, e.g.
the Mines and Works Act (Act 27 of 1956). Although these laws
are not directly aimed at revegetation, they can be applied
to this aspect. In 1980 the law became more stringent and it
became evident that revegetation is not the solution to all
problems, due to deterioration of the vegetation occurring on
many of the revegetated areas.
In order to comply with the demands of the constantly
tightening law, research on the rehabilitation of disturbed
areas started during 1984. The study area included several
mines in the RSA as well as mines situated within the borders
of Leboa and Ka Ngwane. The ecological diversity of these
localities is stressed by the differences in climate, topography,
geology and vegetation. Some of the mines are
situated in areas with an annual rainfall of approximately
400 mm in comparison with others with a precipitation of
more than 800 mm.
Presently, research on the revegetation of road reserves already
indicates that methods and recipes which were successfully
applied in countries with a moderate climate and high
rainfall, do not necessarily produce the same results in the
RSA with its dry and hot summers. This is one of the main
reasons why the use of indigenous grass species was seen as a
priority.
From the results obtained in experiments on the mine dumps
and slimes dams, it was clear that hardy indigenous species
were also not capable of solving all the problems. The negative
results led to a more holistic approach by which the
habitat of plants was taken into consideration.
Special attention was given to soil-associated problems at
various mines. These problems included aspects such as
gradient and length of slopes, particle size of overburden,
chemical imbalances of tailings, temperature of tailings,
spontaneous combustion, etcetera.
Although only a few of the more important factors had been
studied, the results of this research revealed a number of
general
principles which can be applied in devising
rehabilitation strategies. The results can also be used as a
basis for more detailed studies on the various aspects.
The study has shown that every effort should be made to
reinstate a situation as near as possible to the natural
situation. In order to establish a stable and self-sustaining
vegetation on a mine dump, it will be necessary to create a
habitat where ecological factors comply with the tolerance
limits of the species to be used. This approach implies that
the revegetation or grassing alone will not be the answer to
the existing problems of recovering disturbed areas, but that
complete rehabilitation would be of utmost importance.