This technical report presents the preliminary economic assessment for the Minto Mine, covering proposed mineral processing and recovery methods based on historical operations and recent metallurgical testwork.
Report context
This NI 43-101 technical report, effective as of March 31, 2021, was prepared for Minto Explorations Ltd. and 1246778 B.C. Ltd. The report addresses the Minto Mine property, which has a production history extending to October 2018 and further operations from 2019 to the present. The document includes metallurgical testing, mineral processing design, and recovery methods for the proposed operation.
Processing route
Crushing
The proposed process plant design includes a crushing circuit as part of the comminution stage. The report does not provide specific details on the number of crushing stages, equipment specifications, or closed- versus open-circuit configuration for the proposed design.
Grinding
The grinding circuit is identified as a component of the process plant description. No specific mill type, dimensions, power draw, or classification equipment are detailed for the proposed design in the sections extracted.
Flotation
The flotation circuit is described as part of the recovery methods. The proposed design includes flotation as the primary mineral separation process for copper recovery. The report does not specify the number of flotation cells, residence time, or circuit configuration (rougher, scavenger, cleaner stages).
Precious Metals Recovery
A dedicated section titled "Precious Metals Recovery" indicates that the process design incorporates recovery of precious metals, likely gold and silver, although specific recovery methods are not detailed in the extracted text.
Concentrate Dewatering
The proposed process plant includes concentrate dewatering as part of the product handling stage. No specific equipment types (filter presses, thickeners, or dryers) or moisture targets are provided.
Tailings
The tailings management system is identified as part of the proposed process plant. The report references tailings in the context of the overall recovery methods but does not specify tailings disposal method (filtered, paste, or conventional slurry) in the extracted sections.
Plant Consumables
Water
The process plant design includes water as a consumable. No water balance, source, or consumption rates are provided for the proposed operation.
Power
Power is identified as a plant consumable. No power demand, supply source, or backup generation details are provided.
Reagents and Grinding Media
Reagents and grinding media are listed as plant consumables. The specific reagent types (collectors, frothers, modifiers) and consumption rates are not specified in the extracted text.
Process Controls
The report includes a section on process controls, indicating that the proposed plant design incorporates control systems. No specific control philosophy, instrumentation, or automation level is described.
Key reported parameters
| Parameter | Basis | Unit |
|---|---|---|
| Recovery method | Proposed (design) | Flotation |
| Crushing | Proposed (design) | Circuit included |
| Grinding | Proposed (design) | Circuit included |
| Flotation | Proposed (design) | Circuit included |
| Precious metals recovery | Proposed (design) | Included |
| Concentrate dewatering | Proposed (design) | Included |
| Tailings management | Proposed (design) | Included |
| Plant consumables – Water | Proposed (design) | Required |
| Plant consumables – Power | Proposed (design) | Required |
| Plant consumables – Reagents | Proposed (design) | Required |
| Plant consumables – Grinding media | Proposed (design) | Required |
| Process controls | Proposed (design) | Included |
| Partially oxidized (POX) testwork | Testwork | Conducted |
| Production history (to October 2018) | Historical | Documented |
| Production history (from 2019 to present) | Historical | Documented |
Project website: https://www.miningweekly.com/article/minto-closure-sinks-pembridge–2023-06-12
Technical qualifications
This report is classified as a Preliminary Economic Assessment (PEA) and contains cautionary notes including that results are estimates and subject to change, and that there is an element of risk associated with the estimates. The report explicitly states that Mineral Reserves have not been estimated in this study. The report relies on the definitions and disclosure standards of National Instrument 43-101.
Source: "Preliminary Economic Assessment Technical Report for Minto and 1246778 B.C., effective as of March 31, 2021," Sections 1.13 (Recovery Methods), 2.2 (Cautionary Notes), 6.3 (Minto Production History), 13 (Mineral Processing and Metallurgical Testing), 17 (Process Description / Recovery Methods).
