Stage 1 development at Tembang consists of the Belinau deposit, which makes up around 13% of the total Tembang resource of 976,000 ounces gold and 12.79 million ounces of silver.
The remaining resource base will be developed as part of its second stage of operations at Tembang.
The underground mine is expected to have a production rate of 200,000 tonnes per annum and to produce 34,000 ounces per annum of gold over a 3-year mine life.
According to the PFS, Belinau will generate $175.5 million in revenue over the life of mine and project cash flow of $43.5 million.
Cash operating costs for life of mine are expected to be $US511 per ounce.
Stage 1 development of Belinau is expected to cost $A48 million of which $22 million will go towards construction and $22 million towards underground mine development.
The PFS was based on a gold price of $US1500/oz gold and $30/oz for silver.
Sumatra managing director Julian Ford said the PFS underpinned the company's two-stage development strategy.
"The PFS has demonstrated the robust project economics of Belinau as a stand-alone mine for stage one of the Tembang project development, however, we are confident that we will be able to further improve Belinau's economics through additional open pit tonnage from satellite deposits and optimisation studies," Ford said.
The JORC resource for Belinau, which was used for the basis of the PFS, consists of a measured, indicated and inferred resource of 127,000oz of gold and 1.13Moz of silver.
Exploration activity at Tembang dates back to the 1980s when CRA controlled the property.
It was in production from 1997 to 2000, ceasing operations due to the weakening gold price.