Not all bores go to plan… so it is always good to have a plan B, C, and D for recoveries.
Pezzimenti were engaged to complete a 186m long pipejack at Leppington in some non self-supporting saturated clayey ground. At 116m in, the head was flooded by the saturated ground below Scalabrini Creek – see aerial photo.
- Plan A: Pull the head back – not possible so far out from the shaft and the bore would collapse.
- Plan B: Free bore (head only) back from the receive shaft but the ground was not self supporting.
- Plan C: Dig up the head – major approval process had to be undertaken to allow this
- Plan D: (only option) required pipejacking 70m to the original head from the receive shaft and using the original head to push it back out. This is very difficult and requires two crews and good co-ordination.
The retrieval was successful and a credit to the crews, which saved the client having to dig up a protected creek, or Pezzimenti losing a head.