The contract is for the design and construction of the mineral processing and paste fill plant at the $443 million project in Western Australia's Fraser Range.
Work will start immediately and is scheduled for completion in November 2016.
Sirius managing director Mark Bennett said GRES had a good track record build these types of plants in Western Australia.
For his part, GRES managing director Geoff Jones said he looked forward to working with Sirius.
In other news, Sirius also entered into a $3 million contract with Future Power WA for the construction of the 11 kilovolt overhead power line at the Nova project.
Mining at Nova began on Australia Day this year.
The 10-year project is set to produce 26,000 tonnes of nickel, 11,500t copper and 850t cobalt per annum in two separate concentrates.
