Historical Terex S24 Scraper Donated to Upper Waitaki Display

A Terex S24 scraper, generously donated by philanthropist and Rooney Group director Gary Rooney, has been added to the collection of earthmoving machinery on display at the Upper Waitaki Power Development site. This addition highlights the significant role that such machinery played in the excavation and material placement processes that formed the canals linking Lakes Tekapo, Pukaki, and Ohau.

The S24 scrapers, alongside Caterpillar 631 and International 295 units, were crucial in creating infrastructure for the Pukaki High Dam, Lake Ruataniwha Dam, and various powerhouse sites, including Tekapo B and Ohau A, B, and C. In February 2024, Rooney Group transported the S24 scraper to Temuka for restoration, which includes sandblasting and repainting before it officially joins the display.

Heritage Group convener Rick Ramsay remarked on the historical significance of the S24, stating, “There are a lot of operators who will fondly recall the distinctive roar of these machines, and to again see one in the Mackenzie Basin on display is a big addition.” He acknowledged Rooney’s generosity in both donating and transporting the machine.

The S24 scraper is powered by a V12 General Motors two-stroke diesel engine matched with an Allison CLBT-5865 six-speed powershift transmission, allowing for a top speed of 50 km/h. The hydraulic retarder feature enhances the shoe brakes, providing better control during operation. Its bowl capacity reaches 18 cubic meters struck or 24 cubic meters heaped, showcasing its capability for large-scale earthmoving tasks.

Despite boasting over 400 horsepower and a differential lock to prevent wheel spin, these scrapers were primarily push-loaded by bulldozers during the Upper Waitaki project. This was necessary due to the dense glacial moraine deposits that characterized the earthworks. A total of 32 S24 scrapers were sold in New Zealand by Clyde Engineering, with many being utilized in various hydro schemes across the country.

Notable fleet operators included Higgins Earthmoving, Earthmovers Waikato, McBreen-Jenkins, Burnetts Motors, and Doug Hood Ltd. In 1998, Gary Rooney acquired the construction arm of Doug Hood Ltd, which included several S24 scrapers. Their robust construction and ease of maintenance have allowed many of these machines to be rebuilt and continue operating in various capacities to this day.

The unit donated to the Twizel display was one of three purchased by the Rooney Group from the North Island specifically for the company’s Rangitata South irrigation scheme, a private project costing over $130 million. These scrapers were exclusively used for this initiative and remained stored at the company’s depot in Ashburton when not in operation.

The addition of the Terex S24 scraper to the Upper Waitaki display not only serves as a testament to the region’s rich engineering history but also pays homage to the machinery that played a vital role in shaping New Zealand’s hydroelectric landscape.