Unstable rock on an old quarry face was threatening the workforce below. Abcas were employed to provide a team of experienced workers to inspect and remove dangerously loose rock from the face.
Hand tools were used to prise off loose rocks leaving a safe face for workers to continue operating below.
The team were able to access the slope using rope access techniques. The area below the rock face was cordoned off whilst the work was carried out.
Some rock fall netting & associated anchors were installed in other isolated areas of the quarry where scaling was not suitable.
Stabilisation works were required to a 30m high sea cliff following the construction of new properties above.
Access to the crest was severely restricted and the only option was to use rope access techniques. The undercut rock face required a combination of stabilisation methods to ensure it’s long term integrity including:
- Rock bolting of isolated blocks
- Installation of restraint cabling to isolated blocks
- Installation of Geobrugg Tecco mesh support to face
- Installation of Geobrugg Spider mesh support to overhangs
- Installation of rock dowels
- Construction of sprayed concrete scour protection wall at base of cliff
- Sprayed concrete erosion protection to weak areas of face
Rock bolts ranged from 3m to 9m in length and installed into holes of 45-100mm diameter using both fibreglass and high tensile steel anchors. All anchors were cement grouted. Drilling techniques included the use of hand held rock drills, a drifter mounted on a mast and a DTH system for the larger diameter anchors.
All works were completed to the engineer’s satisfaction, contract duration was 4 months.