Modern Mining December 2016

GEOTECHNICAL ENGINEERING

This project was a first as the QUAROX Plus drape system had not previously been used in an application in the mining sector in Africa. The installation of the draping system was managed by Fairbrother Geotechnical Engineering using their own employees and supplemented by seven rope access technicians (RATs) provided by ASC. The proximity of a haul road at the top of the slope allowed for the provision of track-mounted crawler rigs to install the anchor system for the drape mesh at the crest of the slope. This haul road further enabled Fairbrother to provide a more efficient service to the technicians by using a crane to lower the mesh panels into place before send- ing the RATs down the slope to fasten the panels into place. Additionally, to assist the mine with its desired use of the trolley line, a 2 m high berm was constructed in the middle of the road as an exclusion barrier allowing for the trucks to con- tinue hauling payload up the trolley line whilst the RATs installed the drape mesh. Safety was of paramount importance to all the parties and was a non-negotiable on this project. The fast installation methods required that three self-contained teams of RATs work on the slope at the same time clipping the mesh panels together and it was vitally important that there was never a ‘crossover’ between the

For that reason industrial rope access tech- niques were proposed to the mine with the additional sub-contract appointment of a spe- cialist company, Alpinist Safety Consultants (ASC), with a track record of successfully and safely executing difficult drape system installa- tions in the civil engineering market. The Geobrugg Rockfall Drape design soft- ware was used to determine the most suitable and economical solution which resulted in a number of draping options being discussed and a solution negotiated with the client to fit the budget allocated for this slope. The final solution was a combination of 16 500 m 2 of QUAROX ® rolled cable nets (3,9 m x 30 m per roll) overlayed by DELTAX ® mesh (secondary). The superior qualities of QUAROX rolled cable nets compared to conventional cable nets allowed for easier and more efficient installation. No extra work was required before unrolling down the slope which pro- vided for a 30 % reduction in installation time. The QUAROX fits unobtrusively on the slopes and can be colored using powder coating to give it an even better visual appeal. The chain link construction of the cable nets offers much better force transmission than traditional connection by cross clip. Standard support ropes, seaming ropes and shackles are used for the installation.

The installation of the drap- ing systemwas managed by Fairbrother Geotechni- cal Engineering using their own employees and supplemented by seven rope access technicians (RATs) provided by Alpinist Safety Consultants (ASC).

December 2016  MODERN MINING  21