ploughing, or ripping to break up compacted materials, and
addition of fertiliser and/or lime.
3.7.2 Land Restoration Following Mining
or Landfilling
Consent for mining activities now requires that disturbed
land is rehabilitated. Where land is mined the soil cover can
be initially removed and stockpiled and can later be
re-spread over a restored land surface. Land restoration is
relatively straight forward as there is ample experience
available. If the land is sloping, and especially when working with erodible materials, then runoff and erosion risks
during reestablishment must be well mitigated particularly
by establishing vegetation cover as soon as possible.
Whether the original disturbance was a mine or a landfill
site (and many sites are now first mined, then landfilled with
urban waste), the basic considerations for land restoration are
similar. Planning for the final site contour and elevation,
along with end land uses, has to be undertaken at the start of
the project. Topsoil is likely to have to be removed and stored
in safely vegetated sites with the total depth of topsoil piles
controlled (to no more than 1.5 m) to prevent
over-compaction or saturated conditions from degrading the
soil material. At the completion of mining, or filling, the land
surface needs to be restored and recontoured. Often mine
overburden or other subsoil cut-to-waste materials are used.
At some sites, such as the Rotowaro open cast coal mine near
Huntly (Fig. 3.9), the final contour may provide for a better
range of land use options than the pre-existing steeplands. On
landfill sites the subsoil layer needs to provide sealing to
prevent water moving in and gas from moving out except via
gas collection systems that must be installed. To this end
highly compacted clays or liners may be used. The upper
subsoil layers, however, need to be carefully emplaced to
prevent over-compaction so they can be a source of soil
moisture and anchorage for any proposed vegetation cover.
Fig. 3.9 Rehabilitated land (foreground) on Fill Anthropic Soils that was mined for coal at Rotowaro near Huntly. The original site comprised
steep hill country. The restored land has a gentler contour, making it improved for both pastural and forestry land use
3.7 Use and Management of Anthropic Soils
53
addition of fertiliser and/or lime.
3.7.2 Land Restoration Following Mining
or Landfilling
Consent for mining activities now requires that disturbed
land is rehabilitated. Where land is mined the soil cover can
be initially removed and stockpiled and can later be
re-spread over a restored land surface. Land restoration is
relatively straight forward as there is ample experience
available. If the land is sloping, and especially when working with erodible materials, then runoff and erosion risks
during reestablishment must be well mitigated particularly
by establishing vegetation cover as soon as possible.
Whether the original disturbance was a mine or a landfill
site (and many sites are now first mined, then landfilled with
urban waste), the basic considerations for land restoration are
similar. Planning for the final site contour and elevation,
along with end land uses, has to be undertaken at the start of
the project. Topsoil is likely to have to be removed and stored
in safely vegetated sites with the total depth of topsoil piles
controlled (to no more than 1.5 m) to prevent
over-compaction or saturated conditions from degrading the
soil material. At the completion of mining, or filling, the land
surface needs to be restored and recontoured. Often mine
overburden or other subsoil cut-to-waste materials are used.
At some sites, such as the Rotowaro open cast coal mine near
Huntly (Fig. 3.9), the final contour may provide for a better
range of land use options than the pre-existing steeplands. On
landfill sites the subsoil layer needs to provide sealing to
prevent water moving in and gas from moving out except via
gas collection systems that must be installed. To this end
highly compacted clays or liners may be used. The upper
subsoil layers, however, need to be carefully emplaced to
prevent over-compaction so they can be a source of soil
moisture and anchorage for any proposed vegetation cover.
Fig. 3.9 Rehabilitated land (foreground) on Fill Anthropic Soils that was mined for coal at Rotowaro near Huntly. The original site comprised
steep hill country. The restored land has a gentler contour, making it improved for both pastural and forestry land use
3.7 Use and Management of Anthropic Soils
53