Our reinforced soil solution offers several benefits to mine operators: overall cost reduction, reliability and improved flexibility above all
The revamping of Exxaro coal plant in Lephalale, Limpopo, South Africa required the construction of a 12.5m high, 120m long tip wall imposing critical design criteria. Our ‘Paramesh’ MSE wall System, consisting of Terramesh® units with ParaLink® geosynthetic soil reinforcement grids, prevailed over traditional reinforced concrete solutions for its cost-effectiveness and flexibility.
CRITICAL DESIGN CRITERIA
The design phase of the Grootegeluk Medupi Expansion Project required a more strategic solution for a 12.5m high tip wall to accommodate 130 tonne CAT 777 tipper trucks carrying coal deposits, which imposed a very high design criteria of 250 kPa pressure on the wall.
Moreover, the soils utilised in the construction of the wall were overburden coal residue, requiring corrosion resistance to those harsh soils and flexibility to withstand differential settlement.
REINFORCED SOIL PREVAILS OVER REINFORCED CONCRETE
The initial design was carried out by considering a traditional cantilever reinforced concrete wall. Given the resulting costs, we were contacted to submit a different proposal and were able to propose a reinforced soil solution respecting all design criteria and offering a significant construction cost reduction.
Thanks to our in house MacSTARS W software programme for slope stability, we designed a MSE wall offering the following advantages:
- Flexibility: the ‘Paramesh’ system allows for settlement and consolidation without major deformation and structural implications.
- Corrosion resistance: our long-lasting polymer coating ensures protection of the wire mesh against degradation from the harsh filling soils and environmental factors; in addition, our high performance ParaLink® geogrids are amongst the most tried and tested in the world offering 120 year design life and resistance to physical, chemical and biological conditions found in reinforced soil structures.
- Easy and fast installation: Terramesh® units are supplied in standard lengths requiring no cuts on site, saving time during installation; besides, no specialised equipment is required for lifting units into position as all of the materials supplied are compacted and not excessive in weight.
- Environmental friendliness: soil reinforcement using geogrids enables the reuse of on-site materials as structural backfill to the reinforced soil structures, reducing the environmental impact of importing material and transport costs.
- Local job creation: the installation of the Terramesh® units requires minimal skilled labour thus contributing to local job creation.
For further technical details, please find here our case history.