Contact Energy and Pioneer Generation Ltd have a need for very high precision deformation monitoring to ensure the safety of very large and high value assets, located in remote and difficult areas. The challenge was to develop a monitoring system that was sensitive to very small movement change (at the millimetre level) yet simple, robust, low cost and that could be done without highly specialised equipment and software and that could be easily retro-fitted to old dams. Paterson Pitts have developed the “key-ray” method, essentially a long distance electronic extensometer. The method has now been proven over many years on the Cromwell and Roxburgh Gorge landslides and has now been installed on many of Pioneer Generation’s legacy hydro dams in Central Otago, with great success. Paterson Pitts has specialist expertise in high precision deformation survey monitoring and survey control. Other projects have included pitwall and gold processing plant monitoring for Oceania Gold, alignment control for the Tunnel Boring Machine on the 2nd Manapouri Underground Tunnel, Ball Mill and Crane Rail monitoring at Tiwai Pont Aluminium Smelter and geodetic control surveys for Land Information NZ. If your project involves high precision deformation monitoring, contact us for advice.