Euro Sun Mining’s definitive feasibility study (DFS) on the Rovina Valley gold and copper project in Romania has outlined the development of two open-pit mines for a 21,000 t/d operation producing 132,000 oz of gold-equivalent over a 16.8-year mine life.

The company plans to use a phased development approach at Rovina Valley, with the development of the two open pit gold-copper deposits, Colnic and Rovina, included in the DFS and the exploitation of the Ciresata underground deposit (not included in the study) phased in following completion of open-pit mining. Ciresata is envisioned as a bulk underground mining operation and will be evaluated for its economic potential in a later study, the company added.

Estimated initial capital expenditure came in at $399 million (including $12.7 million in pre-strip), with average all-in sustaining costs of $813/oz of gold-equivalent. Using $1,550/oz gold and $3.30/lb copper prices, the post-tax net present value (5% discount) came in at $359 million.

These results were broadly in line with a May 2020 target of outlining a DFS with an 18-year mine life, with initial capital expenditure in line with the preliminary economic assessment – which showed off a capital expenditure bill of $339.7 million.

The Rovina Valley project is planned to be mined with a standard open-pit mining method using articulated trucks and a hydraulic loader. The open-pit mining operation is anticipated to last around 16.5 years, during which the lower-grade material will be stockpiled on a pad close to the primary crusher location for treatment over another 18 months. The DFS incorporates simple flotation without the use of cyanide and dry-stack tailings, the company said.

On the latter, the company said: “KCB have designed a waste management facility within the project area for the co-deposition of waste rock and filtered rougher tailings. Process plant rougher tailings will be filtered in the plant where the resultant filter cake will be transported by conveyors and will be co-mingled with waste rock prior to deposition. The cleaner tails will be filtered separately from the rougher tailings and the resultant filter cake will be transported by conveyors and deposited separately within a lined zone contained within the boundary of the co-mingled facility and will be stored separately in a lined zone of the waste management facility.”

Euro Sun said the design had been engineered to reduce the risk of development of impacted seepage from potentially acid-generating waste rock and capture the impacted seepage from the cleaner tailings.

“After completion of mining the Colnic pit, the waste rock and rougher tailings will be preferentially backfilled into the Colnic pit, while the cleaner tails will continue to report to the lined zone of the waste management facility,” it added.

The company said it is targeting first production from Rovina Valley in 2024.