Sydney Harbour Overwater Sonic Drilling

One of the highlights of 2017 was being involved in the Sydney Metro geotechnical investigation in Sydney Harbour. Legion Drilling was presented with an opportunity to use one of our Sonic drill rigs from an overwater platform in close proximity to the Harbour Bridge. The challenge was that the work had to be completed from a floating barge, as sea floor conditions at the location made the use of a jack‑up barge impractical.

Legion Drilling assembled a specialist team of rig operators and safety personnel to work closely with our client on a comprehensive safety plan and drilling methodology that would give us the best chance of success.

Floating barges have been used for geotechnical drilling in the past, but typically in still‑water environments such as lakes and rivers. This project required setting up the barge in an environment heavily influenced by weather, commercial shipping, and tidal movement.

To mitigate these variables, the works were scheduled late at night when commercial and recreational vessel traffic was minimal. Weather conditions were closely monitored, and emergency crews were on standby to assist if any issues arose during drilling. The operational window was extremely tight — the rig and barge had to be cleared from the location in the early morning hours so shipping routes could reopen. This was non‑negotiable.

Legion Drilling hand‑picked the crew for the job. The three‑man drill crew brought over 30 years of combined drilling experience, supported by an onshore operations and OHS team with an additional 30 years of expertise.

Overall, the drilling program was a resounding success. With careful planning, skilled operators, and a strong commitment to safety, the team effectively managed the challenges of the site. The Sonic drilling technique proved highly effective in achieving full sample recovery from the sedimentary layers and into bedrock.

The accompanying video is a compilation of footage provided by our client and Sydney Metro, originally shared through the Sydney Metro Facebook page and national news broadcasts.