1. Rehabilitation on North Stradbroke Island
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Rehabilitation on North Stradbroke Island

2. What is Rehabilitation?
Rehabilitation is the process of restoring land after mining.
CRL restores, on average, 75 hectares of their leases on North Stradbroke Island each year and has progressively rehabilitated more than hectares of land since 1966.
Stages of Rehabilitation on North Stradbroke Island

3. Pre-mine Surveys
Pre-mine surveys are very important for future rehabilitation of mine sites.
Data collected from flora and fauna surveys can pinpoint the presence of rare, threatened or endangered wildlife and plant species in the mine area. Significant species which occur in the mine path must be re-established in the area after mining. Plant species which do not re-establish naturally or from seed are grown at the plant nursery.
Pre-mine survey undertaken at Yarraman in 1996.

4. Pre-rehabilitation Planning
Environmental officers use satellite imagery, aerial photography, ecological surveys and local knowledge to accurately develop complete vegetation profiles of mine sites. This enables environmental officers to select the correct seed mixes and plant species for post mine rehabilitation.
Amity Air Photo 1996

5. The Rehabilitation Process

6. Step One – Reprofiling of Sand
Dunes are progressively reconstructed by re-contouring the cleaned sand to resemble as near as practicable the original dune’s shape. Restoring the island’s high dunes, (often over 130 metres above sea level), is a complex engineering process.
Cyclone stackers are used to rebuild the dunes.

7. Step Two – Topsoil Spreading
Topsoil is stockpiled and stored on a short-term basis adjacent to the mine path. Dump Trucks replace the topsoil once the sand dunes have been rebuilt. Where possible, topsoil is removed from in front of the mine path (not stored to the side) and replaced directly onto rehabilitation areas. This gives a much better and more vigorous rehabilitation result.
Freshly sown and stabilised topsoil on a revegetated site.

8. Step Three – Direct Seeding
More than 30 species of native seeds are sown together with a temporary crop cover of sorghum into the replaced topsoil. Special fertilisers are also added to replace the nutrients lost in the stored soil.
Native seeds are harvested from lease areas on the island and propagated in the nursery.

9. Seed Harvesting
Roughly 250 kilograms of seed is harvested each year by CRL employees. Seed harvesting occurs on the island, from lease areas. Many different methods are used to collect and treat the seeds, including the use of fire.
Various methods of seed collection at the CRL nursery.

10. The Nursery
Plant nursery production has increased from seedlings in 1996 to now over plants. CRL plants the majority of their nursery stock into 1 to 3 year old rehabilitation.
The plant nursery at CRL.

11. Step Four – Application of Sand Stabilizer
The sand stabiliser used by CRL is a by-product created from the petroleum industry (essentially a biodegradable bitumen). It is called Terolas. Other stabilising methods used by CRL include placing wind fencing, using mulch and laying brush matting on exposed areas to control erosion while vegetation regenerates.
The spraying of terrolas on topsoil.

12. Step Five – Nursery Stock Plantouts
Native seedlings from CRL’s own plant nursery are used to supplement natural regrowth.

13. Step Six – Grass Tree Transplants
Slow growing Grasstrees (Xanthorrhoea johnsonii) are transplanted into the established rehabilitation areas. Each year up to ten mature trees are planted per hectare in addition to 25,000 seeds per hectare.
CRL Grasstree nursery on North Stradbroke Island

14. Step Seven – Maintenance
Log piles, bird perches and nesting boxes are installed to encourage fauna to return to the rehabilitated areas.
Logs and bird roosts on Ibis Rehabilitation
Squirrel Glider

15. Step Eight - Monitoring
Post mining surveys monitor the development and quality of the rehabilitation. These surveys provide valuable data on landform similarity, water quality and level, erosion, vegetation development and fauna recolonisation.

16. Ibis Rehabilitation
Ibis 2002

17. Rehabilitation at Amity
Amity Void 1999
Amity Void Rehab 2007

18. Annual Environmental Reports
Each year, CRL publishes an Environmental Report that provides an overview on environmental management and rehabilitation of mine sites.
Click here for the latest CRL Environmental Report

19. Acknowledgements
Queensland Resources Council wishes to acknowledge Consolidated Rutile Limited for their assistance in the preparation of this presentation.