It comes after the JV was named as the preferred tenderer in April.

The signing of the lump sum, fixed price contract allows work on the processing plant and infrastructure to get underway.

Gold Road managing director and CEO Ian Murray said the award of the EPC contract was another key milestone in the development of Gruyere.

"Importantly, this contract will focus on maximising the local content in the construction of Gruyere and generating significant employment opportunities in the Goldfields region and Western Australia more broadly," he said.

The steel and platework fabrication for the plant will be carried out at Civmec's facility in Perth, creating 30-50 jobs.

Workers will mobilise to the site in August.

The ACJV expects the contract to employ up to 300 people.

Early construction work on the $514 million Gruyere project is underway.

The October 2016 definitive feasibility study for Gruyere outlined a 13-year, 7.5-8.8 million tonne per annum single open pit operation producing an average of 270,000 ounces of gold per annum at all-in sustaining costs of $945 an ounce.

The project has a post-tax net present value of $305 million and an internal rate of return of 20%, using a $1500/oz gold price.

The current gold price is $1660/oz.

The project would generate pre-tax undiscounted free cashflow of more than $1.2 billion over its life, and has a payback period of 48 months.

Gold Fields will manage construction, with first gold due at the end of 2018 or early 2019.

Gold Road shares closed at 71c yesterday, not too far off the 52-week high of 75c reached last month.