Modern Mining December 2015

GEOTECHNICAL

Innovative solution to rockfall

were previously considered too unsafe to mine. In 2013, Wepex, a specialist geotechni- cal contractor based in Durban, South Africa, partnered with global steel manufacturer and supplier Maccaferri and consulting engineers Melis & Du Plessis to undertake the rock- fall mitigation installation at Orapa. One of Debswana’s flagship opencast diamond mines, Orapa was facing some challenges with rocks falling down some of its slopes, particularly during the rainy season. Situated 240 km west of Francistown, Orapa is currently mining at a depth of 250 m and is expected to reach 450 m by 2026. The project – known as the ‘Rockfall Support of Orapa Mine AK1 Pit 805 Ramp and North Eastern Ramp via Drapery Wire Mesh Support project’ – addressed two areas of concern on Orapa’s highwall pit slopes. Both high- walls were above active haul roads that allow

Geotechnical contractor Wepex recently completed a rockfall mitigation installation at Debswana’s Orapa diamond mine in Botswana. The project recently received a ‘Special Mention’ in the prestigious Best Projects Awards organised annually by Modern Mining’s sister magazine, Construction World . The following article is based on the submission for the project entered into the Awards by specialist supplier Maccaferri.

H ow do you limit rocks from be- ing dislodged from the upper areas of degrading slopes in open-pit mines? The answer is simple … you cover the ‘guilty’ slopes of the opencast mine with a big ‘fence’. This was the solution adopted at Orapa and it allows the continuation of mining in areas that

Rockfall protection at Debswana’s Orapa diamond mine. Note the proximity of the haul road.

22  MODERN MINING  December 2015