Mining Studies

Garden Well South Underground

Commodities

Gold

Client

Regis Resources

Location

Laverton, Western Australia

Work Conducted

Feasibility Study

ADVANCING GARDEN WELL (SOUTH) UG

Mining Plus was engaged by Regis Resources to complete the mining portion of a feasibility study (FS) for the Garden Well South (GWS) underground resource. Building on the March 2020 Scoping Study (SS), the FS focused on delivering a detailed mine design, LoM schedule, and declaring a Maiden Ore Reserve for an early 2021 mining commencement.

CHALLENGES

The GWS project faced a range of challenges, including lower-than-expected grades and thickness in the FS block model, resulting in reduced revenue potential compared to earlier projections. The study also needed to address increased water inflows, which raised both capital and operating costs for pumping infrastructure. Balancing the use of inferred material in the LoM plan with the reliance on indicated resources for Ore Reserve viability was critical. Additionally, testing two mining scenarios—paste filling and a minimal-backfill Long Hole Open Stoping (LHOS) approach—required careful economic modelling to determine the optimal strategy for maximising project value.

SOLUTIONS

Mining Plus developed a comprehensive underground mine design, sequence, and schedule based on the updated July 2020 resource block model. Both paste-filling and LHOS-minimal backfill scenarios were analysed in detail to evaluate their economic impact. The selected LHOS method incorporated Cemented Rock Fill (CRF) in high-grade zones, allowing early pillar extraction and efficient hanging wall support. Supporting infrastructure, including the decline and ventilation systems, was strategically placed in the footwall of the shale zone. Mining Plus also conducted a Strengths, Weaknesses, Opportunities, and Threats (SWOT) analysis to identify potential risks and opportunities, ensuring the robustness of the final design and recommendations.

OUTCOMES

The FS reaffirmed the positive economics of the GWS underground project, despite challenges posed by reduced grades and higher water inflow costs. The 2020 Maiden Ore Reserve was declared at a 2.1 g/t cut-off, confirming the feasibility of mining operations. Both FS scenarios demonstrated economic viability, with the minimal-backfill LHOS scenario offering improved flexibility and reduced costs compared to the paste-filling option. Mining Plus successfully provided Regis Resources with a detailed, actionable LoM plan and the necessary data to establish a Maiden Ore Reserve, paving the way for future underground development at Garden Well South.