van Wyk, SJ, van Deventer, PW & Smit, PJL 2009, 'Grassing techniques for surface stabilisation of platinum tailings dams in South Africa', in AB Fourie & M Tibbett (eds), Mine Closure 2009: Proceedings of the Fourth International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, pp. 449-460, https://doi.org/10.36487/ACG_repo/908_34
(https://papers.acg.uwa.edu.au/p/908_34_van Wyk/)
Abstract: The aim of this study is to determine cost-effective grassing methods to stabilise the side slope surfaces of 
platinum tailings dams. Eight dry-land treatments were implemented and analysed after one year to 
determine the minimum fertility requirements to establish a self-regenerating grass cover; to identify native 
pasture grass species that would survive and facilitate bio-system development; and to quantify plant 
production for possible post-mining rehabilitation purposes. Treatment plots of 150 m2 were treated with 
composted materials, inorganic fertilisers, grass, and branch mulch and rock rip-rap and replicated in 
triplicate. Treatment plots were analysed for soil chemical status, plant species reflectance and abundance, 
plant production and plant tissue elemental concentrations. The data after one growing season revealed that 
all treatments had production rates of more than 350 g m-2 dry mass, with higher production on the compost 
treatments. Crown cover exceeded 80 per cent on all plots and the highest basal cover was found to be on 
the grass-mulch treated plots. Rhodes (Chloris gayana (Kunth)) dominated the species frequency with 
noticeable occurrence of Buffalo grass (Cenchrus ciliaris (L.)). Treatments that presented surface roughness 
and the best safe-site conditions with presumably improved moisture retention, presented the best 
establishment results. It was found that pH, electrical conductivity (EC) and exchangeable sodium 
percentage (ESP) values of platinum tailings material were the primary indicators for vegetation 
performance. Concentrations of arsenic (As), molybdenum (Mo), selenium (Se), vanadium (V), chromium 
(Cr) and iron (Fe) found in the grass leaf tissue were higher than those reported in the literature for animal-
safe forage, which renders grazing unsuitable as a land use option. Future studies should focus on 
refinement of the quantities and types of composted material to be applied, the effect of leaching on soil 
nutrient cycling, monitoring of soil and vegetation dynamics on the treated platinum tailings and  land use 
options for the revegetated platinum tailings material.