Björkdal Gold Mineralisation
The Björkdal gold deposit is a lode-style, sheeted vein deposit hosted within the upper portions of the Skellefte Group sediments. To date, the deposit measures roughly 2,000 m in length, 1,800 m in width and extends 600 m deep. Gold can be found within quartz veins that range in thickness from less than one centimetre to more than several decimetres. These veins are usually observed with vertical to sub-vertical dips and strike orientations between azimuth 000° and azimuth 090°. The majority of veins strike between azimuth 030° and 060°. Veining is locally structurally complex, with many cross-veining features observed and thin mineralised quartz veinlets in the wall rocks proximal to the main quartz veins.

Gold-rich quartz veins are most often associated with the presence of minor concentrations of sulphide minerals including pyrite, pyrrhotite, marcasite, and chalcopyrite. Associated non-sulphide minerals include actinolite, tourmaline, and biotite. Scheelite and bismuthtelluride compounds (i.e. tellurobismuthite and tsumoite) are also commonly found within the gold-rich quartz veins, which are typically excellent indicators of gold mineralisation.

Gold occurs dominantly as free gold, however, gold mineralisation can also be associated with bismuth-telluride minerals, electrum, and pyroxenes. Silver is observed as a minor by-product in the Björkdal processing plant, however very little is known about its deportment wi ........

The current environmental permit limits the total Björkdal production capacity to 1.70 Mtpa. In 2019, mining of the open pit was stopped for economic reasons and this production was replaced with ore from the low grade stockpile and an increase in underground production. The remaining open pit material remains economically viable, however, the low grade stockpile realises more value, so open pit mining has been deferred for several years until the stockpile is diminished and open pit production is needed to offset reducing underground production.

The current production strategy is to maximise the underground extraction and delivery to the processing plant with any additional feed requirements sourced from stockpiles.

As presently envisaged in the LOM plan, open pit pre-stripping and production will be restarted in 2025 to supplement the decrease in production from the underground mine.

Underground
The known Björkdal underground deposit lies within a footprint of approximately 1,600 m x 600 m and has a vertical extent of approximately 480 m.

The long-term LOM underground production rate is planned to average 1,135,000 tpa up until 2024, and 648,000 tpa thereafter until production tails off in 2029. On vein development (OVD) will be carried out over approximately four years and stope production will be carried out over approximately eight years. A decrease in production is planned after 2025, when the underground output reduces. ........

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