Grootegeluk Medupi Expansion Project: Maccaferri’s MSE ‘Paramesh’ Wall System Prevailed Over Concrete Retaining Systems

Maccaferri ‘Paramesh’ MSE wall System is a cross product consisting of Terramesh® units with ParaLink® geosynthetic soil reinforcement grids.

Maccaferri was involved by the project executives due to the very critical technical requirements imposed for the erection of a 12.5m-high, 120m-long tip wall at the Grootegeluk mine.  Maccaferri ‘Paramesh’ 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 130t CAT 777 tipper trucks carrying coal deposits, which imposed a very high design criteria of 250kPa pressure on the wall.

In addition, 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, Maccaferri was contacted to submit a different solution and proposed a reinforced soil structure respecting all design criteria and offering a significant construction cost reduction.

Final facts

Thanks to Maccaferri’s in-house MacSTARS W software programme for slope stability, a MSE wall was conceived offering the following advantages:

  • Flexibility: the ‘Paramesh’ system allows for settlement and consolidation without major deformation and structural implications
  • Corrosion resistance: the long-lasting polymer coating ensures protection of the wire mesh against degradation from the harsh filling soils and environmental factors. In addition, Maccaferri’s 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

In conclusion, Maccaferri reinforced soil solution can offer advantages for the mining industry such as overall cost reduction, reliability and improved flexibility.

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