Abseil Access workers have recently completed the first phase of a project which will enable Westport residents to once again have safe drinking water. The workers have secured a hill face with self-drilling anchors and a support drape above a water pipe/tunnel portal. Abseil Access’s safety work has allowed directional drilling and piping contractor Hadlee & Brunton to inject a drill into the portal to clear a tunnel cave-in and replace the water supply pipe which was compromised two years ago.
The original pipe had been in use since 1903 and was well past replacement date when in 2016 some Westporters first noticed the drinking water flowing from their taps was a dark brown colour. The discovery of a tunnel collapse in an inaccessible section of the pipeline led to a part of a hill being demolished, which led to Abseil Access skilled workers being called on to make tunnel access safe.
The cut in the hill to allow access to the pipe portals was a solution the Abseil team led by Ash Rogers came up in in conjunction with GEOadvice engineer Sigfrid Dupre. Work began on the site stabilisation within three weeks of the first site visit.
We installed 23 x 6m SDA grout flush anchors into alluvial deposit, then installed approximately 2500m2 of HR30 PVC mesh. The entire job was completed in five weeks including 8 extra anchors at another site.