San Albino production was designed with processing flexibility in mind at 500MTPD. Design and construction included focus on minimizing cost and time required to double circuit capacity to 1000MTPD. The processing flow sheet includes: two stage crushing, milling, gravity concentration, carbon in leach (CIL) and filtering the circuit tails for dry stacking in the tails storage facility.
Gold is recovered in the San Albino circuit using both gravity concentration and whole ore cyanide leaching using a standard CIL circuit. The gravity gold is produced by leaching the concentrate with a Consep Acacia unit. Gold is produced from the CIL circuit using a standard Zadra carbon strip circuit. The gravity gold production represents approximately 25% of the total production with the balance recovered through the carbon circuit.
The processed tails slurry is filtered using plate and frame filter presses. The presses reduce the moisture content in the tails stream to allow the solids to be dry stacked in a fully lined tails storage facility. The solution removed from the tails stream by the filter presses is reused in the processing facility. The dry-stack tails facility is the first of its kind operating in Nicaragua.
Production began in Q2 of 2021, with commercial production declared in Q3. Annual capability for current design is 180,000 tonnes per year.
San Albino achieved steady state operation in late Q4 and has operated above nameplate design of 500MTPD since the first quarter of 2022. San Albino is capable of doubling capacity to 1000MTPD with a relatively minimal capital investment. The design for the increased throughput was completed with the initial design. A portion of the construction required to double capacity was completed during the initial mill construction as well. Key components required to double capacity to 1000 tonnes per day include: a second Gravity separator and Acacia, a second CIL circuit and increased filtration capacity for dry tails stacking.
The focus remains on optimizing the overall operation and continuing the strong site safety standards.
History & Milestones
- Q4 2019 Procurement of Capital Equipment
- Q3 2020 Completed Installation of Mills and Building
- Q1 2021 Completion of Construction
- Q2 2021 Operations began Production
- Q3 2021 Commercial Production Declared
- Q4 2021 Mill #2 Fully Operational and ready on standby