Mine Site Rehabilitation example essay topic

Rehabilitation is the process of reclaiming land for economical or conservation purposes. This process usually involves re-vegetation. The main aim in rehabilitation is to either return the land to a self-sustaining ecosystem or prepare the land for human use, i.e. crops, pastures and plantations. Rehabilitation should take place at a rate that is significantly higher than natural succession. Several principles are implemented for successful rehabilitation.

Of these principles includes the need for preventing disasters and anticipating problems before they arise, if this is taken to consideration then rehabilitation will be less costly and trouble free. When rehabilitating a site, all the components making up the ecosystem need to be looked at individually. They include soil, climate, vegetation, time and animals. These components need to interact at certain rates in order for the desired effect to be achieved and so might need to be altered. There are other principles of rehabilitation, which will be discussed, in greater detail. There are many methods and strategies involved in rehabilitation which, are specific to a site.

In this case, surface mine reclamation and farmland will be looked at. A step by step illustration of the processes involved will be covered. When rehabilitating mine land, it is important to first prepare a plan before mining takes place. Researching and obtaining data on the floral and faunal elements of the ecosystem by conducting surveys of the upper, mid and under-story species present. If the aim is to restore the land to its original ecological balance and to conserve the species present, then further studies should be conducted on the ecology of the native species, i.e. seed biology of all species. Propagation techniques and the order of re-establishing species should be studied.

When rehabilitation work was conducted on the bauxite mines in the southwest of W.A., special research was conducted on the germination requirements of sown seed. The aim in this case was to re-establish a self-sustaining forest, which maintains water, timber and all the valued qualities of forest. The timing component was carefully considered when removing topsoil in summer to ensure maximum seed store this was achieved when the forest was cleared after seed set took place. Hand seeding was done soon after ripping in order to ensured that the seeds other were well established before germination. When conducting mining operations it is generally desirable that rehabilitation work takes place at the same rate as mining occurs. The soil component in this case needs to be removed in layers (topsoil and overburden) and stock piled during the mining process.

The topsoil is very important because is contains most of the seed, and micro-organisms which are needed for successful re vegetation. Topsoil is often treated with fertilizer after being reapplied as it is already nutrient poor and would not be able to support new plant growth. A major purpose for rehabilitation is to reduce of soil erosion. This also a problem that occurs during the early stage of re vegetation. Young seedlings cannot provide enough protection for the soil as wind and rain move soil particles. It would also be unwise to plant too many small shrubs, i.e. legumes to help combat the problem as they will compete with other seedlings.

Before replacing soil it is important to ensure that the land is reshaped so to resemble the original landscape. Adequate drainage is necessary and can be achieved by deep ripping the soil. This also ensures that the soil is not compacted, well aerated and root penetration is better achieved. Before returning soil to a site, it should be thoroughly tested for toxicity.

It is extremely important to treat affected soil overburden before its returned. When the aim of a rehabilitation project is to return the land to a self-sustaining ecosystem, then a sound understanding of the nutrient cycle is required. The least abundant and most limiting nutrients in Australian soils are phosphorus and nitrogen. Nitrogen is mostly present inorganic matter and is accumulated in the roots of nitrogen fixing plants i.e. legumes.

Most phosphorus can be added as fertilizer. This will aid the initial growth of vegetation but will not sustain the ecosystem's needs. The addition of mycorrhiza l fungi in this case would be most appropriate. Mine site rehabilitation is probably the most involved of all the types. Before any rehabilitation or research is conducted, it is necessary that the post-mined land use be agreed upon.

It would be at the best interest of the mining company to reduce costs. A significant cost reduction strategy is rehabilitating an area in a way that it would require minimum post-mining management. This means that the area will have to be self-sustaining environment. Management can be time consuming and very expensive if feral animals, invading stock of harmful human activity takes place. Pastures and farmland are less affected by such activity and tend to recover quickly as opposed to forests and arid ecosystems. Maintenance after rehabilitation is always necessary, this would include replanting dead seedlings, pest and weed control, fire management, fertilizer application, water during dry periods and the control of soil pH.

So far only mine-site rehabilitation work has been looked at. Farmland rehabilitation or reclaiming devastated land for farming use is considerably different to mine-rehabilitation in that the end result will not be a self-sustaining ecosystem but will require human input for stability to occur. Similar principles apply but are only used when appropriate. The most common sources of farmland degradation include are: Salinity Water erosion Wind erosion Waterlogging Acidification Eutrophication Decline in overall soil condition Most of these factors are interrelated and do not occur exclusively. Water related problems can be solved by increasing water use and introducing good water disposal systems.

The presence of perennial vegetation i.e. remnant vegetation, agro forestry and perennial crops will significantly increase water use because they transpire all year round. Waterlogging, salinity and water erosion can too be controlled by drainage strategies i.e. graded contour banks and reverse interceptor banks (on hills and slopes). Wind erosion is a common factor in farmland degradation and occurs in three different ways. The most major form of wind erosion is saltation which, transports about 50-80% of soil. Suspension and surface creep account for the remainder of the erosion process. Wind erosion can be avoided by planting trees at regular intervals which, will act as wind breaks.

Having some crop or pasture stubble as well as decreasing field size (decreasing saltation) are sound methods of reducing wind erosion. Tilling the land at right angles to erosive winds will also decrease saltation impact. If the farmed land cannot resist degradation effects and preventative methods are ineffective, the nit would wiser to rehabilitate the land so that is self-sustaining. Rehabilitation and reclamation is essential for the conservation of heritage and economically significant land. Land is a precious resource, which is non-renewable.

If rehabilitation does not take place in a disturbed piece of land, that land might continue to erode and never return to its normal functioning capacity. Rehabilitation can be an accelerated form of succession. This process returns the land to its normal stability at a higher rate than if it was left alone. Rehabilitation is an ever-evolving area of study, which involves the manipulation of certain factors to suit unchangeable factors such as climate and topography. Revegetation is perhaps the most common and most effective practice in mine rehabilitation.

It has been proven to stabilize soil, return nutrients to non arable land and increase the aesthetic and economic value of land. Over time rehabilitation has improved and scientists are becoming more accurate in predicting outcomes. The general public too is becoming more aware of the importance of rehabilitation. Community involvement is increasing and rehabilitation laws are being well defined and enforced. It would be unrealistic to assume that in all cases rehabilitation will restore land to its original condition as human impact leaves is permanent mark on the environment. However if rehabilitated land is carefully monitored and managed, the results will almost always be agreeable.

More effort is being invested in rehabilitation and research in rehabilitation as we resources dwindle and conservation is becoming more valued.

Bibliography

AMIC. Mine Rehabilitation Handbook. Australian Mining Industry Council 113, (1990).
Russell J. Hut nik, Grant Davis. Ecology and Reclamation of Devastated Land. Gordon and Breach, New York. (1973) E.
S. Lyle, Jr. Surface Mine Recal mation Manual. Elsevier Science Publishers, New York 1987.
Ward, S. Rehabilitation and Revegetation. In: Best Practice Environmental Management in Mining. Environmental Protection Agency, Canberra (1995).