Authors: Lowry, JBC; Coulthard, TJ; Hancock, GR


DOI https://doi.org/10.36487/ACG_rep/1352_51_Lowry

Cite As:
Lowry, JBC, Coulthard, TJ & Hancock, GR 2013, 'Assessing the long-term geomorphic stability of a rehabilitated landform using the CAESAR-Lisflood landscape evolution model', in M Tibbett, AB Fourie & C Digby (eds), Mine Closure 2013: Proceedings of the Eighth International Seminar on Mine Closure, Australian Centre for Geomechanics, Cornwall, pp. 611-624, https://doi.org/10.36487/ACG_rep/1352_51_Lowry

Download citation as:   ris   bibtex   endnote   text   Zotero


Abstract:
The ability to accurately predict the stability of post-mining landscapes through time scales ranging from decades to thousands of years is a critical element in the assessment of closure designs for uranium mines. In this paper, the CAESAR-Lisflood Landscape Evolution Model (LEM) is used to simulate and assess the geomorphic stability of a conceptual rehabilitated landform of the Ranger Uranium Mine in the Northern Territory, Australia. Crucially, this is the first time that the CAESAR-Lisflood model has been applied to an entire conceptual rehabilitated mine landform. Following construction of the landform and subject to environmental conditions, erosion features such as gullies may erode containment structures, potentially leading to the exposure and transport of encapsulated radioactive material. Further, erosion may lead to increased sediment loads and the transport of other mine-related contaminants off site and into downstream waterways. The CAESAR-Lisflood LEM requires several data inputs to run simulations to assess these processes. Particle size distribution and rainfall data were obtained from field measurements on the Ranger lease, and the Bureau of Meteorology. A digital elevation model (DEM) of the conceptual rehabilitated landform of the mine, which was used to simulate changes to the landform surface under a variety of model scenarios, was generated through the integration of landform design plans supplied by mine operator, Energy Resources of Australia (ERA), with a high resolution LiDAR DEM of the surrounding undisturbed environment. For the purposes of this study, the CAESAR-Lisflood model was modified to enable the differential consolidation of areas representing capped pits on the landform to be modelled. Model scenarios run by CAESAR-Lisflood included the effect of vegetated /unvegetated and consolidated/ unconsolidated surfaces over simulated time periods of 45 and 1,000 years. The 45-year scenarios were used to assess the stability of the landform in the period after the initial construction of the landform once all consolidation had occurred. The 1,000-year scenarios were used to assess the longer-term stability of the landform. Several simulated scenarios identified the potential for large-scale erosion to occur on the landform, potentially exposing buried contaminants. Initial model results provide a guide to areas of improvement in both landform design and the enhancement of the modelling software. The results from simulations of the conceptual landform provide increased confidence that the CAESAR-Lisflood LEM will be able to correctly predict the evolution of a rehabilitated landform once it has been constructed.

References:
ATC Williams (2009) Pit Number 1 Consolidation and Backfill Feasibility Study ERA Ranger Mine, Northern Territory, Report for Energy Resources of Australia Pty Ltd, Document Number 107003R02.
Bates, P.D., Horritt, M.S. and Fewtrell, T.J. (2010) A simple initial formulation of the shallow water equation for efficient two-dimensional flood inundation modelling, Journal of Hydrology, Vol. 387, pp. 33–45.
Coulthard, T.J., Kirkby, M.J. and Macklin, M.G. (2000) Modelling geomorphic response to environmental change in an upland catchment, Hydrological Processes, Vol. 14, pp. 2031–2045.
Coulthard, T.J., Macklin, M.G. and Kirkby, M.J. (2002) Simulating upland river catchment and alluvial fan evolution, Earth Surface Processes and Landforms, Vol. 27, pp. 269–288.
Coulthard, T.J., Lewin J. and Macklin, M.G. (2005) Modelling differential and complex catchment response to environmental change, Geomorphology, Vol. 69, pp. 224–241.
Cull, R., Hancock, G., Johnston, A., Martin, P., Marten, R., Murray, A.S., Pfitzner, J., Warner, R.F. and Wasson, R.J. (1992) Past, present and future sedimentation on the Magela plain and its catchment, in Modern Sedimentation and Late Quaternary Evolution of the Magela Plain, R.J. Wasson (ed), Supervising Scientist for the Alligator Rivers Region Research Report 6, AGPS, Canberra, pp. 226–268.
Einstein, H.A. (1950) The Bedload Function for Sediment Transport in Open Channel Flow, Soil Conservation Technical Bulletin No. 1026, U.S. Department of Agriculture, Washington, DC.
Erskine, W.D. and Saynor, M.J. (2000) Assessment of the off-site geomorphic impacts of uranium mining on Magela Creek, Northern Territory, Australia, Supervising Scientist Report 156, Supervising Scientist, Darwin.
Evans, K.G. (2000) Methods for assessing mine site rehabilitation design for erosion impact, Australian Journal of Soil Research, Vol. 38(2), pp. 231–248.
Hancock, G.R., Lowry, J.B.C., Coulthard, T.J., Evans, K.G. and Moliere, D.R. (2010) A catchment scale evaluation of the SIBERIA and CAESAR landscape evolution models, Earth Surface Processes and Landforms, Vol. 35, pp. 863–875.
Jones, D.R., Humphrey, C., van Dam, R., Harford, A., Turner, K. and Bollhoefer, A. (2009) Integrated chemical, radiological and biological monitoring for an Australian uranium mine – a best practice case study, in Proceedings International Mine Water Conference, 19–23 October, Pretoria, South Africa, pp. 95–104.
Laflen, J.M., Elliot, W.J., Simanton, J.R., Holzhey, C.S. and Kohl, K.D. (1991) WEPP soil erodibility experiments for rangeland and cropland soils, Journal of Soil and Water Conservation, Vol. 46(1), pp. 39–44.
Loch, R.J., Connolly, R.D. and Littleboy, M. (2000) Using rainfall simulation to guide planning and management of rehabilitated areas: Part 2, Computer simulations using parameters from rainfall simulation, Land Degradation and Development, Vol. 11(3), pp. 241–255.
Lowry, J.B.C., Coulthard, T.J., Hancock, G.R. and Jones, D.R. (2011) Assessing soil erosion on a rehabilitated landform using the CAESAR landscape evolution model, in Proceedings Sixth International Conference on Mine Closure (Mine Closure 2011), A.B. Fourie, M. Tibbett and A. Beersing (eds), 19‒21 September 2011, Lake Louise, Canada, Australian Centre for Geomechanics, Perth, Vol. 1, Vol. 2, pp. 613–621.
McQuade, C.V., Arthur, J.T. and Butterworth, I.J. (1996) Climate and hydrology, in Landscape and Vegetation of the Kakadu Region, Northern Australia. C.M. Finlayson and I. von Oertzen (eds), Kluwer Academic Publishers, Dordrecht, pp. 17–35.
Moliere, D.R., Evans, K.G., Willgoose, G.R. and Saynor, M.J. (2002) Temporal trends in erosion and hydrology for a post-mining landform at Ranger Mine, Northern Territory, Supervising Scientist Report 165, Supervising Scientist, Darwin.
Onstad, C.A. and Foster, G.R. (1975) Erosion modelling on a watershed, Transactions of the American Society of Agricultural Engineers, Vol. 26, pp. 1102–1104.
Renard, K.G., Laflen, J.M., Foster, G.R. and McCool, D.K. (1994) The revised universal soil loss equation, in Soil Erosion Research Methods, R. Lal (ed), Soil and Water Conservation Society, Ankeny, Iowa, 2nd edition, pp. 105–124.
Saynor, M.J. and Houghton, R. (2011) Ranger trial landform: particle size of surface material samples in 2009 with additional observations in 2010, Internal Report 596, August, Supervising Scientist, Darwin.
Saynor, M.J., Lowry, J., Erskine, W.D., Coulthard, T., Hancock, G., Jones, D. and Lu, P. (2012) Assessing erosion and run-off performance of a trial rehabilitated mining landform, Life of Mine Conference, Brisbane Queensland 10–12 July 2012.
Supervising Scientist Division (1999) Environmental Requirements for the Ranger Uranium Mine, Department of Sustainability, Environment, Water, Populations and Communities, viewed 3 April 2013, .
Van De Wiel, M.J., Coulthard, T.J., Macklin, M.G. and Lewin, J. (2007) Embedding reach-scale fluvial dynamics within the CAESAR cellular automaton landscape evolution model, Geomorphology, Vol. 90 (3–4), pp. 283–301.
Wilcock, P.R. and Crowe, J.C. (2003) Surface-based transport model for mixed-size sediment, Journal of Hydraulic Engineering, Vol. 129, pp. 120–128.
Willgoose, G.R., Bras, R.L. and Rodriguez-Iturbe, I. (1989) A physically based channel network and catchment evolution model, TR 322, Ralph M., Parsons Laboratory, Department of Civil Engineering, Massachusetts Institute of Technology, Boston, Mass., 464 p.
Wischmeier, W.H. and Smith, D.D. (1978) Predicting rainfall erosion losses – a guide to conservation planning, Agriculture Handbook No. 537.2, U.S. Department of Agriculture, Washington, DC, 85 p.




© Copyright 2021, Australian Centre for Geomechanics (ACG), The University of Western Australia. All rights reserved.
Please direct any queries or error reports to repository-acg@uwa.edu.au