Rehabilitation: other areas
While mining occurs underground, mined areas are backfilled. Mining is carried out from the deepest parts of the mine first and progresses up towards the surface. When mining finishes the portal will be filled and sealed and the area planted. There will be little evidence that any mining activity occurred. A recent example of successful underground mine closure and rehabilitation is Golden Cross, in the Waitekauri Valley near Waihi. That mine closed in 2008.
Crushing and conveying system
At the completion of mining, the crushers will be dismantled, and the crusher slot backfilled. The conveyor, transfer towers and loadout system will be dismantled and removed.
With respect to the conveyor, the Mining Licence states:
‘Upon completion of the project, the land along the conveyor route shall be restored to its former condition unless the relevant territorial authority requires that it shall be left for use as a public walkway or other useful amenity provided that the cost of so doing does not exceed the cost of restoration to the former condition.’
At the completion of mining, a decision will be made as to ultimate use of the conveyor route. If the area was to be restored to its former condition, it would be recontoured, landscaped and revegetated. If it was decided that a walkway should be developed, the walkway area would be appropriately surfaced. It is possible that a walkway could link the whole site, and join with other walkways to include other areas of interest.
While the processing plant site could be restored to productive pasture, it is possible that some equipment could be left in place that could be incorporated into a walkway system. Regardless of that decision, it is expected that most, if not all equipment, structural steel and tanks will be dismantled and removed. All concrete less than a metre below the surface will be broken up and removed. The area will be recontoured. Topsoil and fertiliser will be applied as necessary prior to seeding with agricultural grasses and legumes to establish pasture.
The water treatment plant and reverse osmosis plant are expected to be needed for a period of time after closure. It may be required to treat water from various sources including stormwater runoff from various areas.
Once closure is complete, the water treatment facilities will be transferred to the Trust.