The engineering, procurement and construction contract also involves the associated infrastructure for the plant.
Work will move from the existing interim services agreement to the EPC contract this month.
The EPC contract is expected to take about 18 months to complete.
Sedgman managing director Grant Fraser said the company provided technical expertise to Pumpkin Hollow owner Nevada Copper through various stages of the design process.
"By providing technical expertise during the feasibility, value engineering and front-end engineering design phase of the project, we have been able to develop fit for purpose capital works that meet Nevada Copper's expectations," he said.
The project comprises design, civil, structural, mechanical, piping electrical and commissioning works for the 5000 tonnes per day concentrator.
The Pumpkin Hollow site is located 80km from Reno in Lyon County, Nevada.
Sedgman is part of ASX-listed CIMIC, which has a current market value of about A$16 billion.