Exact Contracting was engaged by Seppeltsfield Wines to construct a 500 megalitre storage dam for their vineyard development at Auburn in the Clare Valley. The dam construction commenced in late January 2019 and was required to be completed by June 2019. The short timeframe was also constrained by anticipated wet winter weather as well as uncertainty of how much rock would be in the dam footprint; hence the project was assisted by a D11 dozer and a fleet of 777 dump trucks. This fleet ensured the bulk earthworks and clay lining could be completed by the start of April, to mitigate the risk of delays the HDPE lining of the dam from wet weather events.
The project scope of works included topsoil strip and stockpile, bulk earthworks, clay lining, HDPE lining and pipeworks. The preliminary geotechnical investigations indicated a hard refusal layer of approximately 52,000m3. Exact Contracting determined that the most suitable course of action would be to blast the refusal layer. Exact engaged A Plus Blast Management to execute the shot firing functions for the blasting, and to provide all bulk and high explosives.
The cut and fill to finished surface was 247,410 m3, which also included a 300mm clay liner layer to cushion the HDPE liner. The 70,000m2 dam lining (1.5mm white on black HDPE geomembrane) was installed to a high quality and within a short time frame and an ELI leak detection survey was conducted upon installation. Exact Contracting processed the excess blasted rock materials at site to also provide for rubble road construction. The project was completed to schedule by June 2019.