Mine Rehabilitation Handbook - Mining and Blasting

7 MONITORING, MAINTENANCE AND RELINQUISHMENT
OF RESTORED MINES
It is essential that monitoring be carried out to verify the success or
otherwise of the rehabilitation program. Reworking may be necessary in
areas where rehabilitation is not performing adequately. Sufficient funds
must be allowed for monitoring, maintenance and reworking.
In Australia, there are no recognised criteria for determining when
rehabilitation is complete. Handing back responsibility for the
management of rehabilitated land to the relevant landowner or
government, instrumentally will often be when an end point satisfactory
to all parties has been reached.
The parameters that may need to be monitored after rehabilitation
include the following:
• the continued safety of the site;
• the establishment and growth of plants including the return of nonsown
desirable species and weeds, percentage of ground cover and
species composition;
• the return of native fauna including insects, birds, amphibians,
reptiles and mammals;
• soil fertility, pH and salinity;
• evidence of erosion or land degradation;
• surface and groundwater quality; and
• condition of adjoining lands.
Maintenance that may be required in addition to rehabilitating any failed
areas includes:
• watering planted seedlings;
• fencing to stop excessive grazing of rehabilitated areas;
• fertilisation;
• pest and weed control; and
• liming to control pH or heavy metals.
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Rehabilitated ecosystems must be sustainable in the long-term.
Rehabilitation can be considered successful when the site can be
managed for its designated land-use without any greater management
inputs than for other land in the area being used for a similar purpose.
Restored native ecosystems may be different in structure to the
surrounding native ecosystems, but the land managers should be
confident that they will change with time along with or towards the make
up of the surrounding area. The rehabilitated land should be capable of
withstanding normal disturbances such as fire or flood.
While the criteria for assessing whether an ecosystem developing on a
rehabilitated site is sustainable in the long-term have not been fully
developed, the issue continues to be a key subject of industry research.
A large number of ‘vital ecosystem attributes’ that may serve as
indicators of ecosystem structure and function have been suggested.
Components of the success criteria could include:
• physical (stability, resistance to erosion, re-establishment of
drainage);
• biological (species richness, plant density, canopy cover, seed
production, fauna return, weed control, biomass productivity,
establishment of nutrient cycles);
• water quality standards for drainage water; and
• public safety issues.
Ecosystem Function Analysis (EFA), a methodology developed by
researchers from the CSIRO to provide indicators of rehabilitation
progress, has been tested on a number of different types of mine around
Australia. EFA may be used widely in the future.
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