Laurion Mineral Exploration - Surface Stockpiles

Surface Stockpiles — Ishkōday Project

Origin and Context

The surface stockpile at Ishkōday originated from the historic Sturgeon River Mine, which operated between 1936 and 1942, producing 73,322 oz gold and 15,929 oz silver from 145,123 t of ore at an average grade of 17 g/t Au.

The stockpile and adjacent tailings represent unprocessed material from this high-grade mine, offering potential for near-term metallurgical evaluation.

2013 Historical Resource Estimate

In 2012 – 2013, GeoVector Management Inc. prepared a mineral resource estimate on the stockpile and tailings, disclosed under NI 43-101 (2011) standards.

Material	Classification	Tonnes	Grade (g/t Au)	Contained oz Au
Stockpile	Indicated	144,070 t	1.59	7,383
Tailings	Indicated	137,501 t	0.67	2,944

This 2012 mineral resource estimate is considered historical in nature. A Qualified Person has not completed sufficient work to classify it as current; LAURION is not treating it as current mineral resources or reserves

Updated Survey and Volume Estimates

Subsequent resurveying by TBT Engineering in 2018 revised the specific gravity range to 2.20 – 2.40 t/m³ and estimated the stockpile volume between 150,000 and 190,000 tonnes, an increase from the original 144,070 tonnes

Metallurgical Test Work (2013 Technical Report)

A 78.3 kg composite sample from the stockpile was subjected to gravity and cyanidation testing, returning:

87.6 % gold recovery by gravity (Knelson Concentrator, 97 % –75 µm)
92–93 % leach extraction via cyanidation
Combined recovery of ≈ 98.5 %, demonstrating the material’s strong amenability to conventional processing

Sonic Drilling and Resampling (2018)

Twenty SONIC holes (185 m total) were drilled through the stockpile to confirm grade continuity and fines distribution.
Results confirmed elevated gold values in fine material (<2 mm fraction ≈ 6.2 g/t Au) and validated internal consistency of the 2013 sampling program

This work also initiated surface- and groundwater baseline monitoring, supporting future permitting for potential processing.

Ore-Sorting Campaigns (2023 – Saskatchewan Research Council)

Two sensor-based ore-sorting campaigns were completed using XRT, laser, and colorimetric sensors:

Laser sorting upgraded average head grade from 5.9 g/t to 10.4 g/t Au ( +75 %) with 74 % efficiency.
Colorimetric sorting achieved a 145 % upgrade (2.63 → 6.44 g/t Au) while rejecting ~ 60 % of waste rock.
Laser + model simulation indicated potential rejection of ~ 69 % waste with < 1 % gold loss

These results suggest that selective pre-concentration could enhance project economics through lower downstream processing volumes.

Reference

For full data, sampling procedures, and QA/QC, refer to:
“NI 43-101 Technical Report — Ishkoday Gold Project, SGS Geological Services (2024)” and “Resource Estimate on the Sturgeon River Mine Waste Pile and Tailings, GeoVector Management Inc. (2013).”

Compliance Note

All quantities, grades, and metallurgical results cited above are historical in nature and not current mineral resources or reserves under NI 43-101. They are presented for context only and should not be relied upon for economic evaluation.