Vista Gold has reported positive results from an updated preliminary feasibility study (PFS) of its Mt Todd gold project in Northern Territory, Australia. The updated PFS is based on the results of metallurgical optimization test work, a redesign of the fine grinding circuit, construction and ramp-up schedule changes, and a comprehensive review of all aspects of the project, including an independent benchmarking study of key PFS parameters.

Highlights of the PFS for a 50,000-metric-ton-per-day (mt/d) project include:

• Unchanged proven and probable mineral reserves estimated at 5.85 million ounces (oz) of gold in 221 million mt at 0.82 grams/mt at a cut-off grade of 0.40 g/mt; 

• Improved estimated annual production of 413,400 oz/y over the life of the project, including estimated average annual production of 495,100 oz/y during the first five years of commercial operations;

• Life-of-mine projected average all-in sustaining costs of $746/oz, including $688/oz during the first five years of commercial operations;

• Projected 13-year mine life; and

• Estimated initial capital requirements of $826 million.

The mine plan calls for processing of 221 million mt over the 13-year operating life of the project. Total recovered gold is estimated at 5.3 million oz. Commercial production is anticipated to begin after two years of construction and six months of commissioning and ramp-up.

The project is designed to be a conventional owner-operated, open-pit mining operation, utilizing large-scale mining equipment in a drill-blast-load-haul operation. Ore is planned to be processed in a comminution circuit consisting of a gyratory crusher, two cone crushers, two high-pressure grinding roll crushers, primary grinding by two ball mills, and secondary grinding by 10 FLSmidth VXP mills. Gold would be recovered in a conventional carbon-in-pulp recovery circuit.

Vista President and CEO Frederick H. Earnest said, “We believe the PFS has substantially de-risked Mt Todd. The metallurgical programs and process area design changes completed by Vista over the past months have confirmed our belief that Mt Todd can achieve excellent anticipated gold recoveries within an attractive operating cost profile.

“Vista’s management believes the PFS reflects significant value creation through Vista’s optimization and development work. We believe project economics are strong at assumed long-term gold prices and quite compelling at today’s market conditions.

“However, we do not believe Vista should develop Mt Todd on its own. The PFS gives us a solid basis for conversations with prospective development partners who we believe will recognize the value of Mt Todd and provide appropriate reward for Vista shareholders.

“To preserve the value of Mt Todd, we are prepared to hold the project until a time when the value of the project appropriately rewards shareholders.”

The Mt Todd PFS was authored by Tetra Tech, with contributions from Mine Development Associates, Resource Development Inc., Proteus EPCM Engineers (a Tetra Tech company), JDS Energy & Mining, and Power Engineers Inc.