Our flexible and cost-effective MacRes® system enabled a tip wall to be built using Kalahari sand as backfill
When QKR needed a retaining wall for their Navachab open-pit gold mine in Namibi, the mine operator turned to Maccaferri Africa for a cost effective and flexible geogrid reinforced MSE wall. What was required was a new loading station constructed with an 8.5m high tip wall. By using our MacRes® system for vertical concrete faced reinforced soil structures we were able to use on-site Kalahari sand as backfill.
The Navachab Gold Mine is near Karibib, in Namibia’s Erongo Region. QKR, the client and main contractor, approached Maccaferri Africa to design and supply the solution. What we built was a tip wall made up of a 8.5m high main wall with two wing walls of varying heights. This created a total facia area of approximately 310m². The structure needed to withstand high loads, including haul trucks equivalent to a load of 25kPa and a jockey slab exerting a dead load of 15kPa.
For this project, we proposed our MacRes® system, which is a soil reinforcement solution that uses our ultra-tough and high strength ParaWeb® geogrids to deliver vertical concrete faced structures that are able to accommodate the massive loads from haul trucks.
Our reinforced soil structures are among the most cost effective in the industry as they are flexible and rapid to construct. They also allow us to reuse on-site materials as structural backfill for the walls, thereby saving cost and time. In this project, we were able to use the local Kalahari sand for backfill and still satisfy the design requirements, by employing our high performance ParaWeb® 50 and 75 geogrids with a maximum tail length of 7m.
Maccaferri Africa provided training to Rocla Pipes, which was responsible for precasting the concrete panels to form the wall’s face. The panels, with a minimal concrete strength of 45 MPa, were cast in Windhoek, Namibia and delivered to the site.
Installation training was also provided to QKR and construction began in mid-September 2017. It was completed at the end of November 2017.
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