Overview
The BS (Blackwater Silver) mine, primarily recognized as the Blackwater Gold-Silver Project, represents one of the most significant mineral processing developments in British Columbia, Canada. Managed by Artemis Gold Inc., this world-class asset is located approximately 112 km southwest of Vanderhoof. The project is distinguished by its massive scale and a phased approach to construction and production, designed to optimize capital efficiency while maximizing mineral recovery from its extensive Proven and Probable Mineral Reserves, which total 596.8 million tonnes grading 0.61 g/t gold and 6.4 g/t silver.
The strategic significance of the BS mine lies in its tiered expansion strategy. The project is designed to transition from an initial Phase 1 throughput of 6 million tonnes per annum (Mt/a) to a robust 15 Mt/a in Phase 2, eventually reaching a nameplate capacity of 25 Mt/a in Phase 3. This phased growth allows the operation to fund future expansions through internal cash flow while establishing a massive footprint in the Canadian mining landscape. The process plant is a sophisticated hybrid facility, integrating traditional comminution with modern leaching and recovery technologies to handle the varied mineralogy of the deposit, which consists of both gold and silver as primary economic elements. With a mine life exceeding two decades, the BS project is a cornerstone of regional economic development and a benchmark for sustainable mineral processing in the 21st century.
Key Process Stages
The mineral processing circuit at the BS mine is engineered for high availability and efficient size reduction, transitioning through several critical stages from Run-of-Mine (ROM) ore to final doré production. The following stages define the current and planned processing flowsheet:
- Primary Crushing: The circuit initiates with a primary gyratory crusher, designed to handle large top-size ROM material. In the expanded phases, this system is optimized to feed multiple processing streams simultaneously.
- Secondary and Tertiary Crushing: Unlike traditional SAG-based circuits, the BS mine utilizes a sophisticated three-stage crushing circuit. This includes secondary cone crushers and tertiary cone crushers (often in closed circuit with screens) to produce a fine-crushed product of P80 – 9.0 mm, which significantly reduces the energy requirements for the subsequent grinding stage.
- Grinding and Classification: The fine-crushed ore is fed into a single-stage ball mill grinding circuit. This stage operates in a closed circuit with hydrocyclones to achieve a final product size of 80% passing 150 microns, ensuring optimal liberation for the gold and silver minerals.
- Gravity Concentration: A portion of the cyclone underflow is diverted to a gravity concentration circuit. This circuit is designed to capture coarse “free” gold early in the process, which is then treated in an intensive leach reactor.
- Pre-Aeration and Hybrid Leaching: The cyclone overflow is thickened and subjected to pre-aeration to neutralize oxygen-consuming minerals. This is followed by a hybrid Carbon-in-Pulp (CIP) and Carbon-in-Leach (CIL) circuit, optimized for the project’s specific gold-to-silver ratio.
- Gold and Silver Recovery: Loaded carbon from the leaching circuit is processed through an elution (Zadra) circuit, followed by electrowinning and smelting in an on-site refinery to produce gold-silver doré bars.
- Cyanide Destruction and Tailings Management: The final tails undergo a cyanide destruction process (using the SO2/Air method) before being pumped to the Tailings Storage Facility (TSF).
Critical Data
The following table summarizes the key design criteria and performance metrics for the BS mine mineral processing facility across its various phases.
| Parameter | Value | Unit |
|---|---|---|
| Phase 1 Nominal Throughput | 6.0 | Mt/a |
| Phase 2 Nominal Throughput | 15.0 | Mt/a |
| Phase 3 Nominal Throughput | 25.0 | Mt/a |
| Gold Recovery (Average) | 93.0 – 94.0 | % |
| Silver Recovery (Average) | 70.0 – 72.0 | % |
| Crushing Plant Availability | 70.0 – 75.0 | % |
| Milling/Wet Plant Availability | 92.0 | % |
| Grinding Product Size (P80) | 150 | µm |
| Estimated Ball Mill Power (Expansion) | Up to 16,800 | kW |
| AISC (LOM Average) | 781 | US$/oz Au |
Technical Details and Sustainability
The technical architecture of the BS mine mineral processing circuit is a testament to modern engineering’s focus on efficiency and scalability. By opting for a multi-stage crushing circuit followed by a ball mill, the design minimizes the risks associated with ore hardness variability, which can often plague SAG mill operations. The use of secondary and tertiary cone crushers allows the plant to achieve a very fine feed for the ball mills, effectively shifting a significant portion of the comminution work to the more energy-efficient crushing stage. This design choice is critical for a project of this scale, as it ensures a more predictable throughput rate across different lithological domains. The expansion study of 2024 further optimized this by planning for dedicated processing streams that share primary infrastructure, such as the ROM bin and primary gyratory crusher, while maintaining independent secondary crushing and milling lines for Phases 2 and 3.
From a sustainability and environmental perspective, the BS mine is at the forefront of “green” mining initiatives in British Columbia. A major technical achievement is the electrification of the project. The mine is powered by a dedicated 135 km, 230 kV transmission line connected to the BC Hydro grid, which provides clean, renewable hydroelectric power. This drastically reduces the carbon footprint compared to mines that rely on diesel or natural gas power generation. Furthermore, the water management system is designed as a near-closed loop, with un-thickened tailings flowing by gravity to the TSF and a dedicated decant return line recycling process water back to the plant. This minimizes fresh water withdrawal and ensures that the project maintains a neutral water balance during average rainfall years.
Engagement with Indigenous groups is another pillar of the BS project’s sustainability framework. The mine is located within the traditional territories of the Ulkatcho First Nation and Lhoosk’uz Dené Nation, with whom Artemis Gold has established comprehensive Participation and Capacity Agreements. These agreements ensure that the processing operations provide long-term economic benefits, including employment and contracting opportunities, while respecting traditional ecological knowledge. As the project moves into its full expansion phases, the integration of advanced automation and data analytics in the processing plant is expected to further enhance metallurgical performance and safety, securing the BS mine’s position as a premier, sustainable gold-silver producer for decades to come.
Source: BS
Source: NI 43-101 Technical Report
This article provides an overview of mineral processing developments based on publicly available technical reports and industry analysis.
