The PEA put the base case after-tax NPV5 at US$364 million and the IRR at a healthy 30.2%.
It envisaged initial capex of $255 million for a 16-year mine in Argentina's Salta province, with a 2.6-year payback.
It was expected to produce an average annual 8 million ounces of silver and 44,300oz gold over the first five years, and an average 4.2Moz silver and 52,000oz gold over the life of mine.
All-in sustaining costs were estimated at $11.97/oz silver-equivalent for the openpit operation.
The PEA used base case prices of $24/oz silver and $1,650/oz gold, compared with today's spot prices of $22.85/oz and $1,794/oz respectively.
The company said there were more opportunities to enhance the project.
It announced last month it would double its Phase II drilling programme to 20,000m ahead of a resource update slated for the second half of 2022.
"Our ongoing Phase II exploration programme continues to intersect multiple high-grade results which are expected to add significant incremental value," president and CEO John Miniotis said.
"Moreover, we have identified several opportunities to further expand and optimise the PEA case, which we intend to evaluate as we proceed towards a feasibility study."
The company, which counts Eric Sprott and SSR Mining among its top shareholders, said it had about C$20 million in cash and was full-funded to advance Diablillos to a construction decision, which was pencilled in for 2023.
AbraSilver also has the La Coipita and Aguas Perdidas projects in Argentina and Rio Tinto can earn up to 75% of its Arcas project in Chile.
Its shares (TSXV: ABRA) have ranged from 31c-82c over the past year and closed down 1.2% yesterday to 40c, valuing it at $189 million (US$148 million).