GOWGANDA SILVER TAILINGS
District-Scale Silver Tailings. Four Decades of Validated Metallurgy.
The Gowganda silver tailings are supported by four decades of independent drilling, metallurgical testing, and engineering work by firms including Watts Griffis & McOuat and GeoVector Management. Nord's January 2026 acquisition of four historic mining leases consolidated the principal tailings deposits and adjacent infrastructure under a single operator for the first time in the district's 116-year history.
REGIONAL CONTEXT
The Cobalt-Gowganda Silver District
The broader Cobalt-Gowganda district has produced over half a billion ounces of silver since 1903. The Cobalt Camp proper accounts for approximately 460 million ounces. The Gowganda satellite camp, 50 km to the west, contributed over 60 million ounces, principally from the Miller Lake O'Brien and Siscoe operations between 1910 and 1972.
The Gowganda tailings sit adjacent to Nord's Castle Mine property, approximately 100 km west of TTL Laboratories in the town of Cobalt. The surrounding region hosts Agnico Eagle's Macassa and Upper Beaver projects, Alamos Gold's Young-Davidson mine, and IAMGOLD's Côté Gold, placing Nord's silver assets within one of northeastern Ontario's most actively mined corridors.
TECHNICAL WORK
Four Decades of Drilling, Sampling, and Engineering
The Gowganda tailings have been the subject of sustained independent investigation since 1981. Each successive program was conducted by a different firm.
1981
Watts, Griffis & McOuat
545 auger + 26 drive pipe holes (1,570 m).
~1.7M tons at 1.45 oz/t Ag, 82% recovery.
Cyanide leach, Lakefield Research.
2000
Sandy K Mines sonic drill program
32 holes in the core area.
Average 2.0 oz/t Ag, 40% above deposit mean.
Concluded earlier resource underestimated by 25%+.
2011
Temex Resources / GeoVector
Metsolve thiosulfate testwork; 764 holes (3,012 m) integrated.
2026
Nord / GeoVector MRE update
860+ holes incl. 103 BMR sonic with multi-element sampling.
Consolidated land package.
Updated estimate expected H2 2026.
GEOVECTOR 2011 TECHNICAL REPORT
GeoVector Management 2011 NI 43-101 Technical Report
GeoVector Management's 2011 NI 43-101 technical report integrated 764 drill holes across three campaigns (1981, 1986–87, 2000) into a block model using inverse distance squared interpolation.
JULY 2011
GeoVector / Temex Resources — NI 43-101 Technical Report on the Gowganda Silver Property
Source: GeoVector Management Inc., NI 43-101 Technical Report, July 8, 2011. Historical estimate; the Company is not treating it as a current mineral resource under NI 43-101 unless reaffirmed by a qualified person.
ACQUIRED LEASES & GEOLOGY
Past Producers Within a Single Contiguous Land Package
The newly acquired BMR leases consolidate four historic past producers — including Miller Lake-O'Brien, Millerett, and Bonsall — onto a single contiguous land package adjacent to Nord's existing Castle Mine and Castle East discovery. All deposits are hosted in the same Nipissing diabase-hosted, native-silver vein system that defines the broader Cobalt-Gowganda camp.
PAST PRODUCTION
Combined historical output exceeds 53 million ounces of silver
Across four contiguous past producers now under Nord's control — Castle-Trethewey, Miller Lake-O'Brien, Millerette, and Bonsall — historical silver production exceeds 53 million ounces. For the first time in the district's history, this production base sits under a single operator, with proximate access to Nord's Castle Mine workings, the Temiskaming Testing Lab in Cobalt, and the Company's planned 600 TPD modular gravity plant — creating one consolidated platform for the next round of resource definition and recovery work.
Miller Lake-O'Brien (oz Ag)
Castle-Trethewey (oz Ag)
Millerette (oz Ag)
Bonsall (oz Ag)
Historical production figures compiled from Ontario Geological Survey and operator records. Historical production is not indicative of any current mineral resource or reserve.
PROCESSING STRATEGY
Processing Architecture: Leach Plant and District Infrastructure
The Gowganda tailings require a hydrometallurgical processing route. Independent metallurgical test programmes have evaluated both cyanide leaching (WGM / Lakefield, 1981) and thiosulfate leaching (Temex / Metsolve, 2006–07), a non-cyanide alternative. These established processing baselines will inform the Company's evaluation of next steps once the updated GeoVector mineral resource estimate is complete.
The silver precipitate produced by the Merrill-Crowe process may be refined at the Company's TTL Laboratories facility in Cobalt, Ontario, which maintains furnace capacity for the production of silver doré. The solid leach residue from silver recovery is expected to contain recoverable quantities of cobalt, nickel, and other strategic metals in arsenide and sulfarsenide form. The Company has validated hydrometallurgical processing routes for arsenical concentrates through independent testwork programmes and intends to evaluate the residue as a potential secondary recovery stream.
District Processing Infrastructure
Beyond the Gowganda tailings, Nord maintains processing infrastructure that serves the broader Cobalt-Gowganda district. TTL Laboratories is the only permitted high-grade milling facility in the Cobalt Camp, operating gravity circuits, a furnace, and an assay laboratory. The Company's 600 TPD modular gravity plant awaits commissioning under the recovery permit framework.
These facilities are designed for feed sources where the silver mineralogy is amenable to gravity concentration. Testwork on Beaver Mine tailings has produced commercial-grade high-grade silver concentrate via gravity recovery (October 6, 2025 press release), confirming that certain district tailings and waste rock streams can be processed through existing equipment. Historical underground workings across the consolidated property also contain broken ore material in stopes that was never hoisted to surface. This material, if quantified through sampling, would represent an additional gravity-amenable feed source.
The phased approach — gravity processing of amenable district materials through existing infrastructure, concurrent with development of a purpose-built leach facility for the Gowganda tailings — supports advancing the Gowganda tailings project through permitting and technical evaluation, with each processing route serving the feed source for which it is metallurgically suited.
PATH FORWARD
Next Steps
Expected H2 2026
Updated Mineral Resource Estimate
GeoVector Management has been retained with two of three original QP authors and all original modelling data. The update will integrate 860+ drill holes across the consolidated land package.
Permitting
Recovery Permit
Advancing under Ontario's 80-day fast-track framework. Specialist permitting consultants and T-Engineering (environmental compliance and paste backfill engineering) are engaged. The Ontario Ministry of Mines has provided an advanced template and confirmed the regulatory pathway.
Underway
Confirmatory Metallurgical Testwork
Tailings samples have been collected. Testwork is underway to confirm the 2007 Temex / Metsolve metallurgical results under current standards and to evaluate both cyanide and thiosulfate processing routes.
Post-MRE
Advancing the project to its next phase
Following completion of the updated mineral resource estimate, the Company plans to advance the Gowganda Silver Tailings to its next phase of project work.
KEY DOCUMENTS
Technical References
SEDAR+ • JULY 2011
NI 43-101 Technical Report — GeoVector / Temex Resources
Leslie Engineering • FEBRUARY 2000
Silver Recovery Project Pre-Feasibility Study — Order of Magnitude Capital Cost Estimate