Ann: Material Increase in Heap Leach Gold Recoveries, page-25

Nearby Mills for Processing Apollo Hill Gold Ore

The Apollo Hill project is situated in a well-established gold mining region, surrounded by major and mid-tier gold producers with processing facilities. The following mills are close enough to Apollo Hill (within a reasonable trucking distance, typically under 150 km for economic toll treatment) and could potentially process its ore:

1. St Barbara’s Gwalia Mine (Leonora)
   • Location: Approximately 40–50 km northwest of Apollo Hill.
   • Details: The Sons of Gwalia Mine, operated by St Barbara Limited, has a processing plant with a capacity of around 1.2 Mtpa (million tonnes per annum). It processes high-grade underground ore but has historically handled various ore types from the region. The mill is equipped for conventional carbon-in-leach (CIL) processing, which aligns with Apollo Hill’s metallurgy (91.8% recovery at 250 µm grind with 56% gravity recovery).
   • Feasibility: The proximity (40–50 km) makes it a viable option for toll treatment, especially if Saturn opts for ore sorting to upgrade feed grades, reducing transport costs. The Gwalia mill’s infrastructure is well-suited for Apollo Hill’s free-milling ore.
2. Dacian Gold’s Mt Morgans (Laverton)
   • Location: Approximately 60–80 km from Apollo Hill, near Laverton (north-northeast of Apollo Hill).
   • Details: The Mt Morgans processing plant has a capacity of around 1.2 Mtpa and is designed for free-milling gold ore, similar to Apollo Hill’s mineralogy. The plant uses a conventional CIL circuit and has processed ore from nearby deposits. Apollo Hill’s high gravity gold content (56%) and low reagent consumption (e.g., 1 kg/t cyanide) make it compatible with Mt Morgans’ setup.
   • Feasibility: The distance is within economic trucking range, and the plant’s capacity could accommodate toll treatment, depending on Dacian’s operational commitments. Ore sorting could further enhance economic viability by reducing the volume of material transported.
     
3. Gold Fields’ Granny Smith Mine (Laverton)
   • Location: Approximately 80–100 km northeast of Apollo Hill.
   • Details: The Granny Smith processing plant has a capacity of around 3.5 Mtpa and uses a CIL circuit to process free-milling gold ore. The plant is one of the larger facilities in the region and has processed third-party ore in the past. Apollo Hill’s coarse grind requirements (e.g., 88% recovery at 4 mm crush for heap leach) and simple mineralogy align well with Granny Smith’s capabilities.
   • Feasibility: The slightly longer distance may increase transport costs, but the plant’s large capacity and compatibility with Apollo Hill’s ore make it a strong candidate for toll processing, especially for higher-grade material post-ore sorting.
     
4. Saracen’s Carosue Dam Operation (Kalgoorlie)
   • Location: Approximately 130 km southeast of Apollo Hill.
   • Details: Operated by Northern Star Resources (following the merger with Saracen), the Carosue Dam processing plant has a capacity of around 3.2 Mtpa and processes free-milling gold ore using a CIL circuit. The facility is designed for large-scale operations and has handled over 1 Moz of gold production. Apollo Hill’s metallurgy, with rapid leach kinetics (75% recovery in 30 days) and low cyanide consumption (0.5 kg/t), is well-suited for this plant.
   • Feasibility: While at the outer edge of economic trucking distance, Carosue Dam’s large capacity and compatibility with Apollo Hill’s ore make it a viable option, particularly if Saturn negotiates toll treatment agreements. Ore sorting could reduce transport costs by concentrating higher-grade material.

Additional Considerations

• Ore Sorting and Toll Treatment: Saturn has demonstrated strong results from laser ore sorting tests at Apollo Hill, achieving a 1.5x grade upgrade (e.g., from 0.78 g/t to 1.2 g/t Au) with 91.9% gold recovery. This technology reduces the volume of material requiring transport (28% volume reduction in tests), making toll treatment at regional mills more economically viable by lowering trucking costs and increasing feed grades.
  
• Heap Leach Potential: Saturn’s metallurgical testing indicates Apollo Hill ore is highly amenable to heap leaching, with 86% recovery over 95 days at a 4 mm crush size and low reagent consumption (0.5 kg/t cyanide, 4.3 kg/t cement). While this supports the potential for a stand-alone heap leach operation at Apollo Hill, it also means the ore could be processed at regional mills with heap leach facilities or compatible CIL circuits.
  
• Infrastructure and Logistics: Apollo Hill’s proximity to Leonora (60 km) and Laverton provides access to excellent infrastructure, including roads for ore transport. The project’s location along the Keith-Kilkenny shear zone places it in a gold-rich region with multiple processing options, enhancing flexibility for toll treatment or future stand-alone operations.
  
• Stand-Alone Mill Potential: Saturn is progressing toward a pre-feasibility study (PFS) for Apollo Hill, targeting a low-cost, bulk-tonnage operation with a 10-year mine life producing 122,000 oz per annum. While toll treatment is viable in the short term, Saturn aims to develop a stand-alone mill to process its 2.03 Moz resource (118.7 Mt @ 0.53 g/t Au)