The PEA outlined average annual production of 112,300 tonnes of copper for 27 years, with 140,000tpy over the first 10 years, from a 120,000 tonnes per day openpit mine and conventional flotation concentrator churning out copper and molybdenum.
The operation would more than double the company's current copper output.
The US$2.1 billion development would yield an after-tax net present value $519 million at a 10% discount rate and an internal rate of return of 13.7% $3.10/lb copper, which increases to $773 million and 15.4%, respectively, at $3.25/lb.
"The Mason PEA demonstrates the success of Hudbay's consistent growth strategy and our team's ability to create value from accretive acquisitions of high-quality copper projects in mining-friendly jurisdictions," Hudbay president and CEO Peter Kukielski said.
"We added Mason to our development pipeline portfolio in 2018 and have since leveraged our integrated core competencies of exploration, mine planning and project development to demonstrate that Mason is a quality long-term development project in our robust organic growth pipeline."
Mason's measured and indicated mineral resource estimates are about twice the size of Hudbay's Constancia and Rosemont deposits. The mine plan includes 1.1 billion tonnes grading 0.34% copper-equivalent, 98% of which is from the measured and indicated categories.
The concentrator design is a similar flowsheet to that used by Hudbay at its Constancia mine in Peru with ore to be fed from the primary crusher to the concentrator via overland conveyor.
Hudbay believes project economics can be enhanced through exploration for higher grade satellite deposits as Mason Valley hosts several historical underground copper mines and highly prospective skarn mineralisation. The company also owns the Blue Hill copper oxide deposit 1.5km away, which was not included in the PEA and could add an oxide component to the Mason project design.
Hudbay intends to complete a geophysical survey to refine the exploration targets in preparation for a potential initial drilling campaign later this year.
Shares in Hudbay Minerals opened up 7% at $8.17, valuing the company at $2.1 billion.