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, Australian Centre for Geomechanics, Perth, pp. 449-460, https://doi.org/10.36487/ACG_repo/908_34
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.
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