Our leadership team brings a wealth of experience and technical expertise. Individually, the members of our leadership team are knowledge leaders in their fields; together they create a dynamic environment of excellence and innovation.

Peter Walkemeyer
General Manager
Peter joined in 2023 as the General Manager for Sedgman Onyx.
With over 35 years of international and domestic experience, Peter is a seasoned executive and project manager who ha...

Chris Grierson
Manager Business and Project Development
Chris was a Director of Onyx Projects prior to the acquisition by Sedgman. Chris now leads the business development and studies teams.
Chris has an extensive commercial and technical kn...

Oliver Holmes
Manager Project Delivery
Oliver has been with Sedgman Onyx since 2018 and was appointed the Manager of Project Delivery in 2023.
Oliver is a multi-skilled professional with a proven track record of fulfil...

Jamie Peters
Group Manager Engineering
Jamie joined Sedgman Onyx in 2019. He was appointed Group Manager of Engineering in 2021 and leads a team of over 100 engineers and designers.
Jamie is...

Andre Kootje
Group Manager- Sustaining Capital
Andre joined Sedgman Onyx in 2021 and was appointed Group Manager of Sustaining Capital in 2023.
Andre is an experienced Project Manager with over 20 years’ experience including over ...

Emilee Macdonald
Business Development Manager and Rio Tinto Relationship Manager
Emilee joined Sedgman Onyx in 2020 and was appointed Business Development Manager in 2024.
Emilee is an experienced Project Management professional with 20+ years’ experience across th...

Michael Black
Manager Project Controls
Michael joined Sedgman Onyx in 2011 and was appointed Manager Project Controls in 2023.
Michael has over 15 years’ experience in project controls and has worked on various major project...

Karl Carter
Deputy Group Manager- Sustaining Capital
Karl joined Sedgman Onyx in 2023 and was appointed Deputy Group Manager of Sustaining Projects in 2024.
Karl has over 25 years relevant experience in Australia, United Kingdom, Europe...