The South32 contract is an extension to an existing contract at Worsley.

The scope of works is to provide civil services or the continuous enhancement of bauxite residue disposal area embankments as well as other civil and road maintenance services. It will start immediately and is expected to complete in 2024.

SRG has also extended a contract with BCI Minerals at its Mardie salt and potash project in WA's Pilbara.

Under the extension SRG will continue to provide earthworks and civil services for the construction of evaporation pond embankment walls, and other civil infrastructure for gas pipeline corridors at Mardie.

The works are expected to be finished this year.

SRG has also secured a three-year marine remediation contract with Fremantle Ports at the Kwinana Bulk Jetty in WA.

That contract includes the design, supply and installation of the hybrid cathodic protection system and concrete maintenance repairs to the jetty.

Those works are expected to be finished in 2024 or 2025.

SRG managing director David Macgeorge said the three contract wins were significant.

"The South32 contract builds on our six-year relationship at the Worsley Alumina site and is evidence of our ability to add value for key clients through our diverse capability," he said.

"The contract extension at the globally significant Mardie salt and potash project demonstrates our ability to provide value-engineered services to our clients from project inception, and the capability to deliver critical infrastructure for the burgeoning salt and potash sector.

"The Fremantle Ports contract is a significant maintenance contract, strengthening SRG Global's portfolio of marine remediation projects."