After rehabilitationThe purpose of rehabilitation is to return the site to an agreed land use aftermining.This is a legal requirement of the EPA (Environmental Protection Authority). Image courtesy of Ensham Resources
Open cut coal mining „Spoil‟ is the overburden removed to reveal the coal seam. Previous spoil is piled behind the pit. In this way, the pit advances, progressively filled with new spoil. Rehabilitation will ultimately occur over the previous spoil behind the mine. Direction of advance of the pitImage courtesy ofEnsham Resources
The Ensham MineThe pit at the Ensham mine is progressing to the right in the picture.Removal of surface overburden is in progress on the highwall side(right) and is dumped on the spoil pile (left) to fill the pit. Image courtesy of Ensham Resources
Rehabilitation planningAn aerial view of the mine showsthe plan for rehabilitation, with theareas to be rehabilitated in green. Image courtesy of Ensham Resources
An Environmental Impact Study(EIS) is conducted to assess theflora and fauna that exists prior tomining.An Environmental Authority (EA) isthen issued with the mining lease toregulate how the mining company isto interact with the environment.The rehabilitation requirements aredifferent for every mine.The mine proposes a rehabilitationplan and the government then addsits own conditions prior to approval.Image courtesy of Ensham Resources
This map highlights areas of“Endangered”, “Of concern” and “Notof concern” ecosystems within andsurrounding the mine site.Image courtesy of Ensham Resources
This map depicts broad types ofvegetation within and surroundingthe mine site.The EA includes the rehabilitationrequirements that must be achievedin ground coverage and speciesdiversity. Image courtesy of Ensham Resources
Before miningImage courtesy of Ensham Resources
After miningImage courtesy of Ensham Resources
RehabilitationImage courtesy of Ensham Resources
Restored landImage courtesy of Ensham Resources
Queensland Resources Councilacknowledges Ensham Resources for their assistance with this presentation and supply of images.
Tel: (07) 3316 2531 Fax: (07)3295 9570 www.oresomeresources.com Rehabilitationon North Stradbroke Island
What is Rehabilitation?Rehabilitation is the process ofrestoring land after mining. CRL restores, on average, 75 hectares of their leases on North Stradbroke Island each year and has progressively rehabilitated Stages of Rehabilitation on North more than 4 000 hectares Stradbroke Island of land since 1966.
Pre-mine SurveysPre-mine surveys are very important for future rehabilitationof mine sites.Data collected from floraand fauna surveys canpinpoint the presenceof rare, threatened orendangered wildlife andplant species in the minearea. Significant specieswhich occur in the minepath must be re-establishedin the area after mining.Plant species which donot re-establish naturallyor from seed are grown Pre-mine survey undertaken at Yarraman in 1996.at the plant nursery.
Pre-rehabilitation PlanningEnvironmental officersuse satellite imagery,aerialphotography, ecologicalsurveys andlocal knowledge toaccurately developcomplete vegetationprofiles of mine sites.This enables environmentalofficers to select the correctseed mixes and plantspecies for post minerehabilitation. Amity Air Photo 1996
Step One – Reprofiling of SandDunes are progressivelyreconstructed by re-contouring thecleaned sand to resemble as nearas practicable the original dune‟sshape. Restoring the island‟s highdunes, (often over 130 metresabove sea level), is a complexengineering process. Cyclone stackers are used to rebuild the dunes.
Step Two – Topsoil SpreadingTopsoil is stockpiled andstored on a short-term basisadjacent to the mine path.Dump Trucks replace thetopsoil once the sand duneshave been rebuilt. Wherepossible, topsoil is removedfrom in front of the mine path(not stored to the side) andreplaced directly ontorehabilitation areas. This Freshly sown and stabilised topsoil on agives a much better and more revegetated site.vigorous rehabilitation result.
Step Three – Direct SeedingMore than 30 speciesof native seeds aresown together with atemporary crop coverof sorghum into thereplaced topsoil.Special fertilisers arealso added to replacethe nutrients lost inthe stored soil. Native seeds are harvested from lease areas on the island and propagated in the nursery.
Seed HarvestingRoughly 250 kilograms of seed is harvested each year by CRLemployees. Seed harvesting occurs on the island, from leaseareas. Many different methods are used to collect and treat theseeds, including the use of fire. Various methods of seed collection at the CRL nursery.
The NurseryPlant nurseryproduction hasincreased from50 000 seedlingsin 1996 to nowover145 000plants. CRL plantsthe majority oftheir nursery stockinto 1 to 3 year oldrehabilitation. The plant nursery at CRL.
Step Four – Application of Sand StabilizerThe sand stabiliser used byCRL is a by-product createdfrom the petroleum industry(essentially a biodegradablebitumen). It is called Terolas.Other stabilising methodsused by CRL include placingwind fencing, using mulchand laying brush mattingon exposed areas to controlerosion while vegetation The spraying of terrolas on topsoil.regenerates.
Step Five – Nursery Stock PlantoutsNative seedlings from CRL‟sown plant nursery are used tosupplement natural regrowth.
Step Six – Grass Tree TransplantsSlow growing Grasstrees(Xanthorrhoea johnsonii) aretransplanted into the establishedrehabilitation areas. Each year upto ten mature trees are planted perhectare in addition to 25,000 seedsper hectare. CRL Grasstree nursery on North Stradbroke Island
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
Step Eight - MonitoringPost mining surveys monitor thedevelopment and quality of therehabilitation. These surveys providevaluable data on landform similarity,water quality and level, erosion,vegetation development and faunarecolonisation.
Annual Environmental Reports Each year, CRL publishes an Environmental Reportthat provides an overview on environmental management and rehabilitation of mine sites. Click here for the latest CRL Environmental Report
AcknowledgementsQueensland Resources Council wishes to acknowledge Consolidated Rutile Limited for their assistance in the preparation of this presentation.