Jokisivu Gold Mine
The Jokisivu Gold Mine (“Jokisivu”) is located approximately 8 kilometres southwest of the Huittinen town centre, some 40 kilometres southwest of the Vammala Plant in southern Finland. The Jokisivu project area comprises 1,083.28 hectares of contiguous mining and exploration tenure that encompasses portion of the prospective Vammala Migmatite Belt.
The first indication of gold mineralisation in the Jokisivu area was identified in 1964. Outokumpu Oy began exploring the area in 1985, with Dragon Mining taking control in 2003 and commencing mining in 2009. Underground development has now extended down to the 590m level, with 2.3 million tonnes grading 3.0 g/t gold being mined from the open-pit and underground operations by the end of 2021.
Geology and Mineralisation
The Jokisivu gold deposit is a Palaeoproterozoic orogenic gold deposit within the Vammala Migmatite Belt in the Tampere Region. The deposit comprises several auriferous quartz vein arrays, controlled by a conjugate set of brittle-ductile shear zones between two major NW-trending shear zones in upper-amphibolite facies.
Mineralisation is hosted within relatively undeformed and unaltered diorite in shear zones that are characterised by laminated, pinching and swelling quartz veins and a well-developed moderately east-northeast plunging lineation. The shear zones also extend into the barren wall rocks. Gold mineralisation is mostly free grains in quartz veins, locally related to arsenopyrite, loellingite, pyrrhotite and scheelite. The mineralisation host rock is surrounded by mica gneisses, volcanogenic and arenitic metasedimentary gneisses and intermediate metavolcanic rocks, most of which have a tonalitic to granodioritic composition.
Production from the Jokisivu Gold Mine commenced with open-pit mining of the near surface portion of the deposit in the Kujankallio area in September 2009. A portal for the decline was established at the eastern most end of the open-pit at a depth of 35 metres.
The near surface portion of the deposit in the Arpola area was also mined by open-pit methods in 2011.
Underground development of the deposit commenced in 2010, with first stoping ore delivered to the Vammala Plant, 40 kilometres to the northeast in January 2011. Underground access to the deposit is obtained from the decline, which is now developed down to the 590m level.
Underground mining is undertaken at Jokisivu by long-hole open-stoping (“LHOS”) with rockfill. Mining advances from the bottom upwards in approximately 80 metre high mining panels, leaving a sill pillar between the panels. Backfill material can be either waste rock from development or waste rock from the surface. Access drives from the main decline to mining areas are developed at 15 to 20 metre vertical sub-level intervals.
Mining of the lode systems is by means of trackless diesel/electric powered equipment such as drill jumbos, front end loaders and trucks. Open stopes are developed over varying heights with floor pillars left at regular intervals. The ore is transported by truck over public roads to the Vammala Plant.
Outokumpu Oy began exploring the Jokisivu area in 1985 and continued sporadically until late 2003, outlining a small, medium to high grade gold deposit. Dragon Mining took control of the project in 2003 and has continued with exploration through to mine commenment in 2009 and beyond.
A total of 1,191 diamond core drill holes have now been drilled at Jokisivu for an advance in excess of 176 kilometres. Mineralisation in the Kujankallio area has been shown by drilling to extend over a 720 metre vertical extent from surface, whilst mineralisation in the Arpola area extends over a 310 metre vertical extent. The Jokisivu deposit remain opens with depth
Drilling continued at Jokisivu throughout 2021, the Company completing 56 underground diamond core drill holes for an advance of 9,396.0 metres. In total six campaigns were completed, targeting both the Kujankallio and Arpola areas.
The initial campaign of 2021 targeted the Kujankallio Hinge Zone (“Campaign 1”) below the 560m level. The 10 hole campaign yielded a series of significant intercepts greater than 1 g/t gold including 3.55 metres @ 6.34 g/t gold, 2.40 metres @ 16.54 g/t gold and 2.60 metres @ 7.86 g/t gold. The 7 hole second campaign (“Campaign 2”) targeted the Kujankallio Main Zone below the 560m level, returning a series of significant intercepts above 1 g/t gold including a best intercept of 9.05 metres @ 2.99 g/t gold.
The third campaign of drilling for 2021 consisted of 16 holes targeting the Kujankallio Main Zone and Kujankallio Hinge Zone from the 560m and 570m levels (“Campaign 3”). This campaign returned a number of significant intercepts above 1 g/t gold, including 2.00 metres @ 10.45 g/t gold, 9.55 metres @ 2.48 g/t gold, 3.90 metres @ 5.74 g/t gold, 6.10 metres @ 4.14 g/t gold and 4.85 metres @ 44.31 g/t gold.
The 6 hole fourth campaign (“Campaign 4”) targeted the Kujankallio Hinge Zone from the 570m level, returning a series of significant intercepts above 1 g/t gold including 4.10 metres @ 5.37 g/t gold, 1.00 metre @ 27.60 g/t gold and 7.25 metres @ 3.51 g/t gold.
Results were received for the 7 hole fifth campaign of drilling for 2021 that was directed at the Kujankallio Main Zone from the 560m level (“Campaign 5”) and the 9 hole sixth campaign that targeted the Arpola area between the 300m and 350m levels from drill stations located on the 350m level (“Campaign 6”). These campaigns each returned a number of significant intercepts above 1 g/t gold, including 5.25 metres @ 7.71 g/t gold, 1.35 metres @ 18.10 g/t gold, 10.50 metres @ 5.04 g/t gold, 3.00 metres @ 9.00 g/t gold and 7.50 metres @ 2.30 g/t gold from Campaign 5. Campaign 6 returned intercepts including 0.75 metres @ 26.30 g/t gold, 3.45 metres @ 5.41 g/t gold, 0.75 metre @ 113.00 g/t gold, 3.90 metres @ 6.64 g/t gold, 13.70 metres @ 6.76 g/t gold, 2.20 metres @ 7.95 g/t gold, 2.00 metres @ 37.75 g/t gold and 5.20 metres @ 4.67 g/t gold.
Drilling will continue at Jokisivu during 2022, the initial campaigns targeting the Arpola area before moving to the Kujakallio area.
Resources and Reserves
The Measured, Indicated and Inferred Mineral Resources for Jokisivu totals 3,200 kt grading 3.5 g/t gold for 360 kozs at 31 December 2021. The Mineral Resource is inclusive of Ore Reserves. It is reported at a 1.3 g/t gold cut-off level, which is based on operating costs, mining and processing recoveries from Jokisivu actuals and a gold price of US$1,800 per troy ounce that has been extrapolated for the potential economic extraction of the resource at a level approximating 120% of the long term average consensus forecast gold price of US$1,500 per troy ounce.
The Proved and Probable Ore Reserve at Jokisivu totals 1,500 kt @ 2.2 g/t gold for 110 kozs at 31 December 2021. The economic in-situ stope ore cut-off grade is based on a variable gold price ranging from US$ 1,730 per troy ounce gold in the short term to US$1,428 per troy ounce gold in the long term that was generated from annual consensus gold forecasts over the mine life period, a EUR:USD exchange rate of 1.16, process recovery of 87%, mining factors and costs.
For further information on the Ore Reserves and Mineral Resources for the Jokisivu Gold Mine refer to the Resources and Reserves page.
On 15 February 2021, a new Environmental Permit was received from the Regional State Administrative Agency (“AVI”). The new Environmental Permit included a significant, but not unexpected bond increase and a few new conditions.
Order 16 of the Environmental Permit, which requires that the waste rock area to be partially rehabilitated before the completion of mining operations has been appealed by the Company to the Vaasa Administrative Court. The Company responded to the Vaasa Administrative Court on 28 January 2022 and expects a decision during late 2022.
The update to the Environmental Permit was required due to the new Jokisivu 2 and Jokisivu 3 Mining Concessions and the need to extend the waste rock area. In recognition of a change in the environmental qualities of some of the waste rock from inert to potentially acid forming, the update included new surface settling ponds and the development of additional water treatment measures.
The presence of a flying squirrel population in the Jokisivu area remains one of the principal environmental issues for the mine. The endangered flying squirrel is protected by the European Union´s Habitats Directive and the Finnish Nature Conversation Act.
A routine investigation into the protected species was conducted in the Jokisivu district during the second quarter of 2018. The results of the investigation indicated the flying squirrel population in the district is exceptionally dense and lively, due to the good nesting and nourishment opportunities on the mine site and surrounding areas. The Company continues to consider, the flying squirrel and its habitat, in its everyday activities.