Overview
Status | Closing / Closed |
Mine Type | Stockpile |
Commodities |
|
Mining Method |
|
Production Start | ...  |
The primary Mishi Mine pit was mined out in 2021. Stockpiled ore at the end of the year was processed in 2022.
Given that the Mishi open pit is currently not part of future production plans, no additional drilling has been completed or is planned since this time as focus for the drilling has been near the Eagle River mine.
As expected, the last of the stockpiled Mishi ore was processed during the First Quarter of 2023. |
Source:
p. 9,30
Contractors
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Deposit Type
- Vein / narrow vein
- Mesothermal
Summary:
Both the Eagle River and Mishi deposits are mesothermal lode gold deposits hosted by Archean Greenstone Belts.
Mineralization is hosted in the Mishibishu Deformation Zone which traverses the property over a 14 km length and is interpreted as a major regional thrust fault which follows a volcanic-sedimentary contact. The northern portion of the property is underlain by mafic volcanic rocks and subvolcanic gabbroic sills. These are overlain to the south by shallow water immature arenaceous/arkosic sediments and polymictic conglomerates, followed by deeper water silts and turbidites progressing southward.
The sequence is overturned dipping moderately north, facing south and striking 90-120º. The deformation zone is 0.5 to 1.0 km wide and characterized by strong ankerite alteration and a schistose fabric dominated by phyllosilicate minerals, sericite and chlorite. Because of the intense deformation, systematic recognition of protoliths and subunits within the deformation zone is problematic.
In the Mishi Mine area, mineralization is hosted by a series of at least 8 tabular parallel zones consisting of ankerite-sericite ± chlorite alteration zones containing 2-8% fine disseminated pyrite and a system of sub conformable, dislocated, smoky grey quartz veinlets and lenses. Veins generally vary from 5-20% of the bulk volume of the zones with individual quartz lenses commonly 5-15 cm wide.
The 8 zones recognized to date are labelled from sout ........

Summary:
The Mishi Open pit operated intermittently from 2002 until early 2021. Mishi ore feed in 2021 and planned in 2022 is all stockpiled material. The Mishi pit was permitted in 2020 to be a temporary storage reservoir for Mill process water, which is to be seasonally pumped back to the Mill site for treatment and ultimate discharge to the environment. There is currently no planned production or Mineral Reserves associated with the site. There is only an Inferred Mineral Resources.
The primary Mishi Mine pit was mined out in 2021. Stockpiled ore at the end of the year will be processed in 2022. As expected, the last of the stockpiled Mishi ore was processed during the First Quarter of 2023.
Flow Sheet:
Stockpiles and Crushing Circuit
There are three stockpile floors that can feed the mill with a front-end loader (FEL). The crushing circuit is a standard two stage process (2CB). From the stockpile a FEL deposits the ore into the jaw crusher. Coarse ore is transported by conveyor to be classified on a double deck vibrating screen. Oversize material goes to the secondary crushing and is reclassified after size reduction (cone crusher is in closed circuit with the vibrating screen). Undersize material is directed to the fine ore bin. The fine ore is transported from the fine ore bin by two conveyors to the primary ball mill (the second conveyor is fitted with a weightometer).
Grinding Circuit
The grinding circuit consists of a primary ball mill followed by a secondary ball mill in closed circuit with hydrocyclones (cyclones). The primary ball mill discharges into the cyclone pumpbox, and the slurry is then pumped to cyclones for classification. Process water (mill solutions) is added to the primary ball mill and cyclone feed pumpbox to obtain the required cyclone feed density. Lime slurry is added to the cyclone pumpbox to target the pH for cyanide leaching and downstream Merrill Crowe circuit.
Cyclone undersize material reports to the secondary ball mill, which also discharges into the cyclone pumpbox. The cyclone overflow is sent to the vibrating trash screen and via gravity, the slurry enters the thickener pumpbox to be pumped to the thickener feedbox. The trash screen oversize is collected in drums and periodically removed.
Flow Sheet:
Summary:

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Reserves at December 31, 2021:
As of December 31, 2022, there were no changes in the Mineral Resources at Mishi compared to December 31, 2021.
Resources are reported using an in-situ marginal cut-off grade of 0.52 g/t.
Category | Tonnage | Commodity | Grade | Contained Metal |
Inferred
|
2,300 kt
|
Gold
|
1.61 g/t
|
120,000 oz
|
Source:

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