Canada

Myra Falls Mine

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Categories

Overview

Mine TypeUnderground
Commodities
  • Zinc
  • Lead
  • Copper
  • Silver
  • Gold
Mining Method
  • Cut & Fill
  • Drift & Fill
  • Sub-level stoping
Backfill type ... Lock
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Mine Life... Lock
ShapshotThe Myra Falls underground Zn-Cu-Pb-Ag- Au mine operated for most of 2023. Increased operating costs and depressed metal prices over a sustained period of time mean the operation is no longer financially viable and the mine was placed on long-term care and maintenance from December 18, 2023. The company will be seeking creditor protection to allow corporate restructuring.

Operations have been episodic since the mine was placed on care and maintenance in 2015. Although the mine restarted in April 2019, it was once again placed on care and maintenance in December, 2023.

Owners

SourceSource
CompanyInterestOwnership
Myra Falls Mine Ltd. (operator) 100 % Direct
Trafigura Group Pte Ltd. 100 % Indirect

Deposit type

  • VMS

Summary:

The Myra Falls orebody is a classic Volcanic Hosted Massive Sulphide (VHMS) deposit. It is a composite of sulphide lenses that were emplaced in a very dynamic, rapidly changing environment of submarine volcanism, massive debris flow, and constant tectonic activity. This active period was followed by a time of quiet, widespread sedimentation (cherts and argillites). The second cycle of volcanic activity and mineral emplacement subsequently occurred producing the Lynx-Myra-Price deposits.

Sulphide ore deposits are structurally controlled along narrow rift and trough features that have produced a system that is at least 10 km in length. The Myra ore deposits are situated in a Paleozoic group of rocks known as the Sicker Group, which comprises four main lower units that make up the stratigraphic package hosting the Price Deposit. The units that are proximal to the project area are the Price Formation, Myra Formation, Thelwood Formation, and Flower Ridge Formation. The Myra and Price Formations are unconformably overlain by the rocks of the Thelwood Formation and the Flower Ridge Formation.

The H-W Horizon (H-W Rhyolite and Sulphide Facies) and the Lynx-Myra-Price Horizon are the main oreproducing units at NMF. The HW Horizon is the oldest unit of the Myra Formation. It is predominantly a rhyolitic volcano-sedimentary package, comprising coarse volcaniclastics, sandstones, and mudstones, with massive quartz-feldspar porphyry bodies near the top of the horizon. The horizon may be further subdivided to include massive to semi-massive sulphide, chert, argillite-silt, fine to medium-grained rhyolitic volcaniclastic rocks, coarse-grained rhyolitic volcaniclastic rocks, ore clast breccias, and quartz-feldspar porphyry.

Massive to semi-massive sulphides occur in thick lenses, up to 35 m thick, of massive and banded ore, within the H-W Horizon. These sulphide lenses form the HW, Extension, Battle, and Ridge Zone orebodies, and the smaller more discontinuous and un-mined Marshall and Trumpeter Zones.

The Lynx-Myra-Price Horizon is a deformed and discontinuous rhyolitic package that occurs near the top of the Myra Formation and hosts Lynx-Myra-Price mineralization. The thickness of the rhyolitic unit is variable, ranging from 1 to 45 m thick. The unit consists of massive and bedded, fine to coarse-grained quartz-feldspar phyric rhyolitic volcaniclastics, laminated chert and massive and semi-massive sulphides in the Lynx, Myra and Price orebodies. The dominant sulphide species are chalcopyrite, pyrite, sphalerite and galena, and the orebodies of this horizon may be characterised by abundant barite.

The alteration mineralogy at Myra Falls includes sericite and silica with subordinate chlorite, albite, and carbonate. Sulphide mineralogy of pyrite+/-chalcopyrite+/-sphalerite+/-galena+/ tennantite is also present in varying modal percentages as disseminations and veinlets. The overall depth and lateral distribution of the hydrothermal system for the Myra Falls deposits has not yet been defined. Zones of pyrite stringer mineralization have been observed to underlie the H-W, Battle, Lynx and Myra deposits (Juras, 1987). Sinclair (2000) has identified three main mineral assemblages that occur within the Myra Falls stratigraphy. These are a polymetallic Cu-Pb-Zn-Fe rich mineral assemblage that can be found within the H-W, Battle Gap, Extension and Ridge zones, a Cu-rich mineral assemblage that is typically a basal unit and found in close relation to the bottom of the sulphide mineralization, and a late stage Ag-Au rich assemblage that is commonly associated with the upper mineralized units of the H-W Horizon.

Reserves

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Mining Methods

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Comminution

Crushers and Mills

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Processing

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Production

Myra Falls restarted zinc production during September 2018 and first shipment of zinc in concentrate took place in Q4 2018.
CommodityProductUnits20182015
Zinc Concentrate kt 0.417
Zinc Metal in concentrate kt 0.69
Lead Concentrate kt 0.020.5
Copper Concentrate kt 0.12.7
Copper Metal in concentrate kt 0.10.6
Silver Metal in concentrate koz 28209
Gold Metal in concentrate koz 0.64
Lead Metal in concentrate kt 0.2

Operational metrics

Metrics20232022202120182015
Daily milling capacity  ....  Subscribe  ....  Subscribe  ....  Subscribe
Tonnes milled  ....  Subscribe  ....  Subscribe  ....  Subscribe45 kt of ore145 kt of ore

Production Costs

Commodity production costs have not been reported.

Heavy Mobile Equipment

Fleet data has not been reported.

Personnel

Mine Management

Job TitleNameProfileRef. Date
....................... Subscription required ....................... Subscription required Subscription required Mar 1, 2024
....................... Subscription required ....................... Subscription required Subscription required Feb 29, 2024
....................... Subscription required ....................... Subscription required Subscription required Feb 29, 2024
....................... Subscription required ....................... Subscription required Subscription required Mar 1, 2024
....................... Subscription required ....................... Subscription required Subscription required Mar 1, 2024

EmployeesYear
...... Subscription required 2023
...... Subscription required 2022
...... Subscription required 2017
...... Subscription required 2014

Aerial view:

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