van Wyk, SJ, Hatting, J & Haagner, ASH 2019, 'Wind erosion design considerations for closure of tailings storage facilities in South Africa: a case study', in AB Fourie & M Tibbett (eds), Mine Closure 2019: Proceedings of the 13th International Conference on Mine Closure
, Australian Centre for Geomechanics, Perth, pp. 1185-1200, https://doi.org/10.36487/ACG_rep/1915_94_van_Wyk
Environmental pressure is ever mounting on mining companies to prove that mine residue facilities will be stable landforms after closure. Designing tailings storage facilities (TSFs) for reduced dust emissions is also not readily considered as part of the tailings engineering process, and most TSFs are still uncovered in South Africa. This paper advocates proactively engineered, wind resistant tailings landscapes by incorporating principles of aerodynamic design into final closure design content. This is imperative in the wake of much dryer, windier, and warmer climate predicted for sub-Saharan Africa. This paper considers tailings specific wind erosion scenarios modelled from field data for a large TSF in South Africa. The revised wind erosion equation is applied to determine comparative wind erosion scenarios for geometric variation that informs the landscape engineering process. The methodology considers local climate, surrounding regional relief (wind direction and energy scenarios), TSF construction methodology (particulate grading and segregation), geometrical design (wind speed amplification), and material physical and chemical characteristics (particle size, moisture regimes, and dispersion properties). The modelled output demonstrates that wind erosion exponentially increases on unprotected slopes with an increase in slope angle comparing 14, 18, and 26° slope angles, implying that uncovered tailings landscapes should be designed much flatter to withstand wind erosivity over time. Mitigation scenarios are incorporated into the model to evaluate effectiveness of surface protection considering the scale of high dust risk areas and the degree of effectiveness that can be expected. The outcomes of this study suggest that unless the substantial effects of wind are not considered during the geometrical design and final closure landscape planning stages, uncovered tailings landscapes will remain serious sources of dust pollution. A case is made that wind erosion should be incorporated as a matter of principle closure design of TSFs.
Keywords: wind erosion, tailings dust, closure design, revised wind erosion equation
Amponsah-Dacosta, F & Blight, GE 2002, ‘The effects of wind on the surfaces of mine tailings dams’, Proceedings of the 33rd Conference of the International Erosion Control Association, Orlando.
Blight, GE 2008, ‘Wind erosion of waste impoundments in arid climates and mitigation of dust pollution’, Waste and Resource Management, vol. 26(6), pp. 523–533.
Fryrear, D W & Saleh, A 1993, ‘Field wind erosion: Vertical distribution’, Soil Science, vol. 5, issue 4, pp. 294–300.
Fryrear, DW, Saleh, A, Bilbro, JD, Schomberg, HM, Stout, JE, & Zobeck, TM 1998, Revised Wind Erosion Equation (RWEQ), Wind Erosion and Water Conservation Research Unit, United States Department of Agriculture-Agricultural Research Service, Southern Plains Area Cropping Systems Research Laboratory Technical Bulletin No. 1.
Hagen, LJ 1991, ‘A wind erosion prediction system to meet user needs’, Journal of Soil and Water Conservation, vol. 46, pp. 106–111.
Haagner ASH, Jansen van Rensburg, I, Champion G &Van Wyk, SJ 2014, ‘Dust Risk Assessment and Management Plan for a South African mine heading towards closure’, Proceedings of the 9th International Mine Closure Conference, Johannesburg.
Liebenberg-Enslin, H 2014, A functional dependence analysis of wind erosion system parameters to determine a practical approach to wind erosion assessments, PhD thesis, University of Johannesburg, Johannesburg.
Pasak, V 1967, Factors underlying the wind erosion of soils. In Dvorak & Novak 1994. Soil Conservation and silviculture. Elsevier. Amsterdam, pp. 401p
Queney, P 1948, ‘The problem of air flow over mountains: a summary of theoretical studies’, Bulletin of the American Meteorological Society, vol. 29, pp. 16–25.
South African Weather Service 2008, Ba-Phalaborwa weather station, viewed 5 August 2010,
Shao, Y 2008, Physics and Modelling of Wind Erosion, Springer, Berlin, p. 420.
Singh, AB 1994, Wind erosion: Mechanics of saltation and dust generation, PhD thesis, unpublished, Texas Tech University, Lobbock.
Stout, JE & Zobeck, TM 1996, ‘The Wolfforth field experiment: A wind erosion study’, Soil Science, vol. 161, issue 9, pp. 616–632.
Rademeyer, B 2007, The influence of Environmental impacts on Tailings Impoundment design, PhD Thesis, University of Pretoria, Pretoria.
Van Wyk, SJ 2010, Dust Management Best Practice Guideline for Tailings Storage Facilities, internal guideline document prepared for AngloGold Ashanti, p. 154.
Van Wyk, SJ 2015, Revised Dust Management Best Practice Guideline for Tailings Storage Facilities, internal guideline document prepared for AngloGold Ashanti, p. 168.
Vermeulen, NJ 2001, State of Gold Tailings, PhD Thesis, University of Pretoria, Pretoria.
Visser, SM 2004, Modelling Nutrient Erosion by Wind and Water in northern Burkina Faso, PhD thesis, Wageningen University, Wageningen.