Sibelco Australia is a world leader in progressive rehabilitation practices.
We are committed to securing NSI’s long-term sustainability through world-class environmental management. Our rehabilitation programs are based on a deep understanding of NSI’s unique ecosystems. On average, Sibelco Australia rehabilitates 75 hectares of mining lease area per year with increases to 125 hectares planned for the coming years. We combine information from pre-mine surveys and environmental management programs to deliver the following eight-step rehabilitation process:
Step 1 – Re-Profiling
As our mine operations advance sand dunes are progressively reconstructed by re-contouring the tailings to resemble the original dune’s shape.
Step 2 – Topsoil Spreading
Top soil is spread to a depth of 50mm to 100mm. Topsoil management is important because it is a natural seed bank, containing nutrients and micro-organisms, and has a higher moisture capacity than ordinary sand.
Step 3 – Sowing
On average approximately 250 kilograms of native seeds are harvested each year by Sibelco Australia employees. These seeds are sorted and stored to be used as seed mix appropriate for each area of rehabilitation. Based on the results of pre-mining vegetation surveys, a native seed mix of up to 30 species are sown together with a temporary crop cover of sterile hybrid sorghum and spread directly over the dunes using a tractor. The sorghum which is fast growing helps to prevent erosion and provides protection to native seedlings as they develop.
Terolas, biodegradable bitumen, is also applied during this stage to stabilise the dune until the native species germinate and become established.
Maintenance fertiliser is applied six to 10 months after direct sowing.
Step 4 – Rehabilitation Maintenance
Placing wind fencing and laying brush matting helps stabilise the mine site area further,and controls weeds and erosion while vegetation regenerates.
Step 5 – Tubestock Planting
Approximately eighteen months after the rehabilitation process began, the, site receives tubestock plantouts from the Sibelco plant nursery to supplement natural regrowth. Plant nursery production has increased from 50 000 seedlings in 1996 to more than 150 000 per year.
Step 6 – Grasstree Re-Location
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.
Step 7 – Habitat Construction
Log piles, bird perches, nesting boxes and other techniques are used to encourage fauna to return to the rehabilitated areas.
Step 8 – Monitoring and Maintenance
Post mining surveys monitor the development and quality of the rehabilitation. From these surveys we collect valuable data on landform stability, vegetation development, fauna recolonisation and soil nutrients.
Sibelco Australia’s extensive environmental management and monitoring program includes: water quality, air quality, noise, fauna and flora.
Monitoring of rehabilitation vegetation is a long term commitment for the company. It is divided into five components:
- Initial establishment monitoring to assess the quality of early rehabilitation
- Long term monitoring provides detailed information on the development of post-1987 rehabilitation and compares sites with representative unmined reference areas
- Broadscale monitoring provides a broad general assessment of the rehabilitation development over most of the block and ensures no significant problems have been missed
- Monitoring of pre-1987 rehabilitation reveals the standard sites have attained
- Specific research trials designed to address particular problems and enable continuous improvement.