Milestone achieved at Prominent Hill: RKF ES delivers on Wira Shaft breakthrough

RKF Engineering Services (RKF ES) is proud to mark a major milestone in BHP’s Prominent Hill Operations Expansion Project (PHOX), located in South Australia, with breakthrough to the bottom of Wira Shaft successfully reached in May 2025. The shaft is now one of the deepest strip and line shafts in Australia, extending to a depth of 1,331 metres.

The PHOX project aims to expand the production capacity of BHP’s Prominent Hill mine. RKF ES, alongside project principal BHP and other contracting partners Byrnecut, pitt&sherry and concrete producers Jetcrete and Hallet, played a critical role in delivering the design and shaft construction phase of the project. Since the first shaft excavation cut in December 2023, the team completed 199 firings, deploying over 18,000 m³ of the super workable concrete via slickline to construct the shaft lining. RKF ES and our geotechnical subcontractor Douglas Partners were responsible for the design of the concrete shaft liner.

During construction, concrete mix design and 24/7 technical oversight of concrete supply and quality control was provided to BHP, which included concrete and materials testing delivered by RKF ES with support from our subcontractor, Construction Sciences. Remote access cameras were installed to enable offsite technical oversight and improving real time assessment and decision making on concrete batching and conveyance and optimising production and construction build rates without compromising the integrity of the liner.

RKF ES’ role in PHOX continues our legacy of providing expert design and material solutions for major shaft infrastructure, with a portfolio spanning Australia, Canada and the United Kingdom. Our experience in shaft design and high-performance concrete is helping shape the future of deep shaft development, globally.

Looking for expert advice on your next project? Reach out to the team at RKF ES.