Table 8. Supervising Scientist position on proposed Landform closure criteria RMCP reference Proposed Landform closure criteria Assessment outcome Relevant Rehabilitation Standard L1 Supervising Authority confirms all items removed with the exception of those agreed under ER 2.3. Accepted – L2 Supervising Authority confirms all tailings are placed into the pits. Accepted – L3 Modelling predictions of final conceptual landform show tailings are not exposed for at least 10,000 years. Further Information To be completed in the initial approval.
L4 A digital elevation model (DEM) of the final constructed landform is captured. The DEM is then rerun with the final land surface topography to ensure tailings are not exposed for at least 10,000 years. Further Information Landform Stability: A DEM of the constructed landform matches the approved landform design, within applicable construction standards. Modelling of erosion on the constructed landform matches results of erosion modelling conducted on the approved landform
L6 Drainage channels are designed and installed on the outcomes of LEM model predictions for gully erosion. Accepted – L7 Design of channels will be to blend in with the constructed landform. Further Information – L8 Post observations show drainage channels are in good condition (e.g. remain functional structures). Further Information – season
L9 Post observations show no unplanned erosion has occurred. Accepted Landform Stability: Annual inspections show that there is no gully formation occurring above the buried tailings. L10 No bedload coming offsite. Accepted Landform Stability: Annual inspections show that no bedload is transported away from the constructed landform, in the absence of active management. trial trial season
L11 Event suspended sediment load, evaluated across the wet season, to Magela and Gulungul creeks are approaching background loads. Further information Landform Stability: fine suspended sediment loads, measured in Magela and Gulungul creeks at the downstream boundary of the Ranger Project Area, are approaching background values.
Table 14. Supervising Scientist position on proposed Radiation closure criteria RMCP reference Radiation criteria Assessment outcome Relevant Rehabilitation Standard R1 Using the agreed restrictions on land use the total above-baseline radiation dose from external gamma exposure, inhalation of radon decay products (RDP), inhalation of dust and ingestion of bush food (including water), (shall not exceed) 0.3 mSv per year. Accepted Public Radiation Projection: Dose constraint: 0.3 mSv in a year — effective dose to members of the public is ALARA below the dose constraint for conditions of agreed future land use. R2 Should land use restrictions fail the radiation dose from external gamma exposure, inhalation of RDP, inhalation of dust and ingestion of bush food (including water), (shall not exceed) 1 mSv per year. Accepted Public Radiation Projection: Dose 1.0 mSv in a year — effective dose to members of the public is ALARA below the dose limit for conditions of future land use different to those agreed. R3 Total above-baseline radiation dose rate to terrestrial plants and animals from internal and external exposures (shall not exceed) 100 μGy h–1 to the most highly exposed terrestrial species. Accepted Environmental Radiation Projection: Environmental reference level of 100 μGy h–1 for terrestrial organisms — absorbed dose rates to the most highly exposed individuals are ALARA below the environmental reference level R4 Total above-baseline radiation dose rate to aquatic plants and animals from internal and external exposures (shall not exceed) 400 μGy h–1 to the most highly exposed aquatic species. Accepted Environmental Radiation Projection: Environmental reference of 400 μGy h–1 for aquatic organisms — absorbed dose rates to the most highly exposed individuals are ALARA below the environmental reference level
EE9 Ecosystem similarity and sustainability Monitoring EE9. Developing monitoring methods for revegetation. EE9A. How do we optimise methods to measure revegetation structure and sustainability on the rehabilitated site, at a range of spatio-temporal scales and relative to the areas surrounding the Ranger Project Area? Cross Theme KKN No. ER Link Category Title Questions CT1 Biodiversity and Ecosystem Health Risk CT1. Assessing the cumulative risks to the success of rehabilitation and to the protection of the offsite environment. CT1A. What are the cumulative to the success of rehabilitation and to the offsite environment? CT2 Heritage values Heritage Values CT2. Characterising World Heritage values of the Ranger Project Area. CT2A. What World Heritage Values are found on the Ranger Project Area, and how might these influence the incorporation of the site into Kakadu National Park and World Heritage Area?