Mine Closure - Mining and the Environment: From Ore to Metal - page 826

FIGURE 21.7
Development of Gully Erosion at the
Early Stages of Rehabilitation
Adequate design of land form and
drainage followed by years of mainte-
nance is a prerequisite for successful
rehabilitation.
Supplementary plantings are commonly made in the case of canopy trees, including
some climax species, which need to be shaded during the i rst few years of establishment.
These species would not survive if planted in the initial programme.
Frequently, routine monitoring of rehabilitated areas reveals bare patches requiring
follow-up treatment. It helps if the reason for bare patches can i rst be deduced so that
follow-up treatments can be selected which overcome whatever factor prevented the veg-
etation from establishing. Common causes of bare areas include: uneven distribution of
seed, gaps in topsoil application, the presence of acidic material at or near the surface, or
localized erosion. Follow-up treatment may also be required in cases where vegetation dies
after the initial establishment. This may be caused by a phyto-toxic agent including acidic
soil or seepage, or by dessication due to dry conditions. Lime can be applied to neutralize
small acidic areas. In seasonally dry areas, it is common for water to be applied during the
i rst dry season after the initial establishment.
Other types of maintenance that may be applied include weed control, and fencing to
exclude grazing by wildlife or livestock during the period that vegetation is becoming
established.
For agricultural or silvicultural land uses, repeated cycles of planting and harvesting
with appropriate maintenance, are normal, and apply whether or not these systems are
established on rehabilitated land. However, where natural vegetation is being established,