Land rehabilitation

From Wikipedia, the free encyclopedia

Land rehabilitation is the process of returning the land in a given area to some degree of its former self, after some process (business, industry, natural disaster etc.) has damaged it. Many projects and developments will result in the land becoming degraded, for example mining, farming and forestry.

While it is rarely possible to restore the land to its original condition, the rehabilitation process usually attempts to bring some degree of restoration. Modern methods have in many cases not only restored degraded land but actually improved it, depending on what criteria you use to measure 'improvement'.

[edit] Mine Rehabilitation

Modern mine rehabilitation aims to minimize and mitigate the environmental effects of modern mining, which may in the case of open pit mining involve movement of significant volumes of rock. Rehabilitation management is an ongoing process, often resulting in open pit mines being backfilled.

After mining finishes, the mine area must undergo rehabilitation.

Waste dumps are contoured to flatten them out, to further stabilise them against erosion.
If the ore contains sulfides it is usually covered with a layer of clay to prevent access of rain and oxygen from the air, which can oxidise the sulfides to produce sulfuric acid.
Waste dumps are covered with topsoil, and vegetation is planted to help consolidate the material.
Dumps are usually fenced off to prevent livestock denuding them of vegetation.
The open pit is then surrounded with a fence, to prevent access, and it generally eventually fills up with ground water.
Tailings dams are left to evaporate, then covered with waste rock, clay if need be, and soil, which is planted to stabilise it.

For underground mines, rehabilitation is not always a significant problem or cost. This is because of the higher grade of the ore and lower volumes of waste rock and tailings. In some situations, stopes are backfilled with concrete slurry using waste, so that minimal waste is left at surface.

The removal of plant and infrastructure is not always part of a rehabilitation programme, as many old mine plants have cultural heritage and cultural value. Often in gold mines, rehabilitation is performed by scavanger operations which treat the soil within the plant area for spilled gold using modified placer mining gravity collection plants.