Case Studies

Standards for the Supply and Application of Hydromulch Products, Stage 1 — Critical Shear Testing

The research reported in this document constitutes Stage 1 of a broader research programme. Specifically, it aimed to test the critical shear strengths of a range of hydromulch products with varied application rates. Paper clearly did not perform well relative to the other hydromulch fibres. Treatments generally failed due to the bond between the mulch and soil surface breaking, rather than the mulch itself being torn. From the results, lighter applications, excluding paper, gave similar resistance to shear as did standard applications. This is due to the overriding impact of guar gum on critical shear at low rates of hydromulch fibre. Download case study: Standards for the Supply and Application of Hydromulch Products, Stage 1 — Critical Shear Testing (PDF 1.38MB)

A Comparison of the Effects of Different Hydromulch Materials on Infiltration, Runoff, Erosion, and Evaporation

A study using simulated rain and overland flows was carried out to assess the effectiveness of a range of hydromulch materials in increasing infiltration, reducing erosion, and reducing the rate of drying of the soil surface. Data analysis showed all the hydromulched plots (as a group) to be considerably different to the Control plots. Differences between the various hydromulch types were relatively small in comparison. Across all the variables considered, the Paper hydromulch ranked consistently as the least satisfactory of the hydromulch materials, generally being statistically significantly poorer than Flax plus paper and Sugar Cane treatments. For most variables, Flax plus paper and Sugar Cane were not significantly different, and ranked as the most satisfactory of the hydromulch treatments. Download case study: A Comparison of the Effects of Different Hydromulch Materials on Infiltration, Runoff, Erosion, and Evaporation (PDF 984k)

Outer Batter Slope Profile Design for the Beenup Tailings Storage Facility

Following the decision of BHP Billiton to close its Titanium Minerals mining operation at Beenup, Landloch was engaged to design an outer batter slope for the Mine Development Storage Area, (MDSA) that would remain stable over the long term.

Laboratory studies on materials (ferricrete and sand) found at the site determined that, after some initial erosion, the ferricrete ‘amoured’ and its erosion rates diminished greatly. The sand displayed higher levels of initial erosion than the ferricrete.

Computer simulations using the Water Erosion Prediction Program (WEPP) assessed a variety of batter slope designs for the MDSA. The long-term erosion of the most suitable slope profiles was then assessed using the SIBERIA model. It was determined from the laboratory studies and computer simulations that the most effective batter slope design was a concave slope of ferricrete material. Download case study: Outer Batter Slope Profile Design for the Beenup Tailings Storage Facility (PDF 57k)