CRL has revolutionised mining of North Stradbroke Island’s high sand dunes by developing environmentally sustainable rehabilitation processes.

Using information from our pre-mining surveys and environmental monitoring, CRL uses an eight-step rehabilitation process to restore the mine site land:

Step 1: The dunes are progressively reconstructed by recontouring the tailings to resemble the original dune’s shape as our mines move through the landscape.

Step 2: Dump Trucks replace the 50mm to 100mm of topsoil, which is an important resource because it is a natural seed bank, contains nutrients and micro-organisms, and has a higher moisture capacity than ordinary sand. The remaining topsoil (second cut) is stockpiled and stored on a short-term basis adjacent to the mine path for later use.

Step 3: More than 30 species of native seeds are sown together with a temporary crop cover of sterile hybrid sorghum and spread directly over the dunes using a tractor. Roughly 250 kilograms of seed is harvested each year by CRL employees. Maintenance fertiliser is applied six to ten months after direct sowing.

Step 4: Planting sorghum crops, spraying terrolas (a biodegradable bitumen), placing wind fencing and laying brush matting help stabilise the mine site area and control erosion while vegetation regenerates. 

Step 5: Native seedlings from CRL’s own plant nursery are used to supplement natural regrowth, where necessary. Plant nursery production has increased from 50,000 seedlings in 1996 to more than 130,000 plants in 2005. We plant the majority of our nursery stock into the previous year's rehabilitation.

Step 6: 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: Log piles, bird perches, nesting boxes and other techniques are used to encourage fauna to return to the rehabilitated areas.

Step 8: 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.