Precious metals developer Sabina Gold and Silver has announced optimisation to the plan for its Goose mine, at the Back River district in Nunavut.
The updated feasibility study of February 2021 contemplated a mill producing 3 000 t/d for the first two years, increasing to 4 000 t/d in year two with a sustaining capital cost for the expansion of about C$17-million.
As part of the updated study, an initial 4 000 t/d mill was considered. However, at the time, the settled tailings density was based on the previous pre-leach thickener test work. This work resulted in a lower Echo openpit tailings capacity and a decision to delay the mill expansion timeline.
Sabina says that since the updated feasibility study, completion of detailed geotechnical test work on the tailings samples and the inclusion of a high-capacity tailings thickener, the tailings storage capacity of the Echo openpit has increased sufficiently to enable the decision to construct the mill at a 4 000 t/d capacity at the outset. This, in addition to optimised equipment selection and detailed engineering, has reduced the cost of the expansion to C$10-million.
The current mine plan includes the complete mining of the Echo openpit and seven quarters of mining from the Umwelt openpit during the construction phase of the project. As per the feasibility study, this provides 2.2-million tonnes of stockpiled ore containing 373 000 oz of gold, including 936 000 high-grade tonnes at 8.4 g/t gold prior to commissioning of the mill.
In addition, the current mine plan includes an additional 3.5-million tonnes mined in the first three years of operations, enabling 4 000 t/d of mill capacity without the need to increase the mining rate or modify the existing mine plan.
The Back River permitting was completed based on a maximum 6 000 t/d mill capacity and thus no additional permitting or authorizations are required for this modification.
“We are pleased that additional test work has resulted in this conclusion,” says Sabina president and CEO Bruce McLeod. “It is the option that makes sense from an operational and cost perspective and has the potential to improve payback by delivering increased gold production in the earlier stages of the mine life.”
The Goose mine is the first mine on the 80 km Back River Gold district.