Twenty workers have lost their jobs at Perilya mine in Broken Hill after a maintenance contract being carried out by Macmahon was handed to a smaller contractor.
The contract change is expected to save the company $4 million.
Jetcrete's operations manager, Paul Ferguson, said the company would retain 33 people working on the previous contract.
The company has also made a commitment to employ a fully residential workforce.
"We wanted to look after the local guys here and what I do like about Broken Hill, we originally had as part of our original contract we had some FIFOs in there but we made the decision to make this a fully residential position so that includes all the Jetcrete guys as well," he said.
"We've relocated them so that they now live in Broken Hill."
Ferguson said senior Macmahon managers not picked up by Jetcrete would likely be redeployed to other projects.
However, around twenty operator jobs have been cut, ABC reported.
The CFMEU said while it is unfortunate not all employees could be retained, it welcomed to the move by Jetcrete to implement a fully residential workforce.