St. Barbara Planning New Mining Method for Gwalia

St. Barbara Ltd. has reported a new lifeof- mine (LOM) plan for its Gwalia gold mine near Leonora, south-central Western Australia. Based on existing resources and reserves, the new plan includes a change in mining and haulage methods to suit the deepening mine and the nature of existing unmined lodes. The new mining approach, termed Gwalia Mass Extraction (GMX), is assumed to begin in year four of the plan and is enabled by the company’s Gwalia Extension Project, currently under construction.

A prefeasibility study (PFS) of the new LOM plan indicates that Gwalia could produce at least 200,000 ounces per year (oz/y) of gold during St. Barbara’s fiscal years 2023 to 2029. The PFS also indicates an opportunity to convert more of Gwalia’s existing total mineral resources into mineable reserves, with geotechnical conditions remaining manageable at the proposed depths. Exploration work continues, seeking to further extend resources.

Changes in the new LOM plan are primarily focused on delivering higher production rates and lower unit costs beyond Gwalia’s current five-year outlook, which remains robust without GMX. Essentially, the new plan involves a move to island-pillar mining methods for narrower lodes, with increased mining rates, and matching that with increased haulage rates by moving to hydraulic hoisting, with underground comminution and pumping of slurry to surface.

St. Barbara Managing Director and CEO Bob Vassie said, “I am pleased to report a strong and profitable five-year outlook for the Gwalia mine. The A$100 million Gwalia Extension Project is well under way and will start to deliver the benefits once paste aggregate fill is commissioned this financial year.

“The adoption of a new approach to mining our orebody will allow the mine to continue strongly past the five-year outlook period, such that Gwalia will continue to be the cornerstone asset for the company and provide us with a stable foundation on which to pursue value-adding growth initiatives.”

As featured in Womp 2018 Vol 04 -