MINING METHOD
Various mining scenarios were analyzed for Tonopah, considering different processing strategies and economic inputs. The base case used an Au price of US$2,150 per troy ounce (oz) and involved a combined processing approach: a 2,000 tonnes per day (tpd) mill and an 8,000 tpd heap leach facility, with final pit selection maximizing resources and economic margin. A mining recovery of 100% and 0% dilution were assumed for pit optimization and scheduling. Au recovery was assumed at 92% for the mill and 75% for the heap leach. Based on the chosen Au price, the cut-off grades (COGs) are 0.18 grams per tonne (g/t) Au for heap leach, 0.28 g/t Au for mill feed, and 0.76 g/t Au as the break-even grade between the two processing routes.
The mine design features three pit phases, each tailored to prioritize higher-grade material early and manage pre- stripping efficiently. Access and haul roads, ramp geometry, and bench configurations were optimized for 100-ton class equipment, maintaining safety and operational efficiency. Waste rock storage was strategically planned to accommodate both current and future needs. Approximately 16% of waste rock was planned to dump within the pit, a strategic move that significantly reduced costs as the mine approached closure.
Production planning is focused on maximizing project net present value (NPV) while maintaining practical equipment requirements and minimizing fluctuations in mining rates. The schedule fills both mill and heap leach circuits to capacity when possible, prioritizing high-grade material for the mill and routing lower-grade material to the heap leach. The COGs and material routing ensure that mineral processing is both efficient and economically advantageous, with only minimal rehandling of material required.
Supporting the mine plan is an owner-operated equipment fleet, including 3 Caterpillar (CAT) 992 front-end loaders, 8 to 11 CAT 777 haul trucks, 3 CAT MD6250 drill rigs, and ancillary support vehicles, all sized to match production targets. This approach leverages local skilled labour, ensuring strong mineralized material control and operational flexibility. The overall strategy is designed to maintain a steady production profile, efficient resource utilization, and adaptability for future expansion or modification based on ongoing operational results and economic factors.
Ultimate Pit Design
Life of Mine Production Schedule
MINERAL PROCESSING AND METALLURGICAL TESTING
Scoping-level metallurgical studies were undertaken by various operators, including Kennecott (1994-1996), Newmont (2003) and Midway Gold (2006 to 2009) for the Tonopah property which was primarily focused on testing higher-grade vein and breccia type material. Additional test work was commissioned by Viva between 2018 and 2023 and completed by Resource Development, Inc (RDi), McClelland Laboratories (MLI), and KCA; which form the basis for process conclusions. These results indicate that Au and Ag mineralization from the Tonopah project are amenable to recovery by gravity concentration and cyanide leaching with the following recommended parameters:
- Heap Leach Parameters:
- Crush size of 100% passing 12.5 millimetre (mm)
- Variable recoveries for Au and Ag based on head grade and material type with an overall Au recovery of 76% for grades of 0.5 g/t or less for both volcanic and argillic material types and Ag recoveries of 15% and 19% for Ag grades of 1.0 g/t or less for argillic and volcanic material, respectively
- Design leach cycle of 120 days
- Agglomeration will be required with an estimated cement addition of 4.0 kilograms per tonne (kg/t) material
- Cyanide consumption of 0.26 kg/t material
- Mill parameters:
- Grind size of 80% minus 106 µm (micron) (150 mesh)
- Au recovery of 95% for argillic material and 90% for volcanic material
- Ag recovery of 36% for argillic material and 38% for volcanic material
- 48 h leach residence time
- Lime addition of 0.60 kg/t material
- Cyanide consumption of 0.58 kg/t material
In general, the Tonopah deposit shows some variability in recoveries by the two primary material types with heap recoveries for Au being more sensitive to head grade than product crush size. Coarse Au is present in some of the material and may be contributing to the lower recoveries for high-grade heap leach material. Au recoveries for milled material were consistently high at both 106 and 75 µm grind sizes (150 and 200 mesh) and gravity pre- concentration is recommended to recover coarse Au particles.
Recovery Methods
Mineralized material from the Project will be processed by a combination of heap leaching and milling with Carbon-in-Leach (CIL) recovery at a combined rate of 10,000 tpd, including 8,000 tpd of low-grade heap leach material and 2,000 tpd of high-grade mill material.
Mineralized material will be crushed to 100% passing 12.5 mm using a three-stage closed crushing circuit. High- grade and low-grade material will be campaigned through the crushing circuit and stockpiled separately using a radial stacking conveyor. Low-grade material will be reclaimed from the low-grade stockpile and agglomerated with cement, which will also act as a pH buffer, before being conveyor stacked in 10 m lifts onto a permanent geomembrane-lined heap leach pad and leached with a dilute cyanide solution. The resulting pregnant leach solution will flow by gravity to a pregnant solution tank before being pumped to a carbon adsorption circuit. Au values will be loaded onto activated carbon and then periodically transported off site to be toll-processed, where the loaded carbon will be stripped and regenerated before being returned to the project for re-use. Barren solution leaving the adsorption circuit will flow by gravity to a barren solution tank before being pumped back to the heap.
High-grade material will be reclaimed and ground to 80% passing 150 Mesh (106 µm) in a single stage ball mill which will operate in a closed circuit. Lime will be added to the high-grade material for pH control before being fed to the ball mill along with process solution. Ball mill discharge will be pumped to a hydrocyclone cluster for classification with a portion of the cyclone underflow being diverted to a gravity concentrator for the recovery of coarse metal with the remaining cyclone underflow being returned to the ball mill feed. Cyclone overflow material will be thickened before reporting to a six-stage CIL circuit where the thickened slurry will be mixed counter-flow with activated carbon and will flow from one stage to the next through carbon interstage screens. Sodium cyanide (NaCN) will be added to the first three CIL tanks as needed. Leached slurry leaving the last tank will be discharged as tailings to a tailings thickener before being pumped to a filter feed tank, filtered using a filter press, and dry-stacked using trucks onto a dedicated portion of the heap leach pad. Loaded carbon from the first tank of the CIL will be toll-processed along with carbon from the heap leach circuit.
PROJECT INFRASTRUCTURE
The Project is accessed by paved SR 376 and Nye CR 82. Nye CR 82 will need to be relocated during the project development. Internal site roads will be primarily dirt roads which will connect the site and process facilities for access.
The Project will use a combination of pre-fabricated office trailers and pre-engineered steel buildings for operations. Buildings considered include administrative and process office trailers, a site laboratory, mine truck shop and warehouse facility and roof over the milling facility.
Power for the operation will be provided to the project site via an existing 15 kV power line which runs along the eastern side of the property and is only lightly utilized. The line connects to the Nevada Energy power grid and may be upgraded under existing permits to a 25 kV service and is assumed to have sufficient capacity, to meet the project needs. Power from the existing line will be stepped down and distributed using overhead power lines at 4.16 kV, 3 phase, 60-hertz (Hz) and will be further stepped down to 480-volts (V), 220 V and 110 V as required. Power will be supplied to Motor Control Centers (MCCs) or distribution panels at 4160 V for motors above 373- kilowatts (kW) (500 horsepower [hp]) and 480 V for 220/110 V for motors below 373 kW and low voltage systems. All overhead distribution lines will be connected to a main switchgear which will include synchronization, control panels, disconnects, circuit breakers, instrumentation and data logging.
Raw water will be provided by production wells and will be pumped to a head tank for distribution to other areas. A portion of the head tank will be used to provide fire water storage. Potable water is planned to be delivered to the site from Tonopah via truck and distributed using a potable water storage and transfer pumping system.
Note: Information summarized from Preliminary Economic Assessment NI 43-101 Technical Report, Tonopah Gold Project, Nevada, USA dated August 20, 2025, and filed on SEDAR August 21, 2025.
