Tunnel Inspection with Aurecon and Essential Energy

ROV Innovations has recently conducted in depth inspections of a flooded tunnel and pipeline with Aurecon for Essential Energy in Nymboida, just south of Grafton, NSW. The inspection posed a few irregular problems, including accessing the tunnel, 30m down a shaft, as well as navigating the old infrastructure within the shaft to get to the sections of tunnel which needed to be inspected. 

The turbidity of the freshwater river feeding the tunnel was average, however the high definition video capabilities enabled us to capture vision enabling the Aurecon tunnelling engineers to confidently compile their reports for Essential Energy.

Nymboida Hydro Power Plant

Setting up the ROV above the shaft

The 30m shaft was initially inspected using a combination of Unmanned Aerial Vehicles (UAVs) for the areas above water, and the High Definition Seamor ROV for all underwater components of the shaft. Initial penetration within the tunnel was 145m downstream from the shaft to a concrete bulkhead and butterfly valve for inspection, then to inspect the 500m upstream from the shaft to the river intake, as well as a visual review of the old intake at Nymboida River.

Lowering the Seamor ROV down the 30m deep shaft

Intake Valve at Nymboida River

Intake Valve at Nymboida River

Entering the tunnel from the Nymboida River intake.