Rajapalot is located 8 kilometres to the east of the Rompas vein trend. The style of mineralization at Rajapalot is predominately sulphidic and of a disseminated or replacement style, which differs from the nuggety vein style observed at Rompas. Rajapalot is the primary target area for the Company.
Surface sample highlights Rajapalot include prospecting grab samples taken from outcrop that returned 2,817 g/t gold, 2,196 g/t gold, 1,245 g/t gold, 933 g/t gold, 151 g/t gold and 135.5 g/t gold. A total of 52 grab samples from the Rajapalot prospect to date average 152.8 g/t gold and range from 0.001 g/t to 2,817 g/t gold. All samples are prospecting grab samples. These are selective by nature and are unlikely to represent average grades on the property.
Discovery grab samples from the Rajapalot project returned gold mineralization from three distinct areas, namely the Palokas, Joki and Rumajärvi prospects. The areas were targeted with regional geophysics and surface soil geochemistry. Rumajärvi lies 1.5 kilometres south of Palokas, while Joki is located 1 kilometre southeast of Palokas. Each prospect area is characterized by minor outcrop on a topographic high, within a predominantly swampy terrain and therefore very little in situ bedrock has been located. Little outcrop has been found between the prospect areas. As the same mineralized rock types occur in outcrop, the glacial boulders sampled and reported here are considered to be proximal to their source.
In October 2013, Mawson announced the first core test of Rajapalot from the Palokas prospect. Drilling intersected:
- 9 metres at 10.2 g/t gold from surface, including 3 metres at 27.5 g/t gold from PRAJ0003;
Palokas is part of the Rajapalot area, located 8 kilometres east of our drilling in the vein style mineralization at Rompas. Further high grade, thick and near-surface core sample results include:
- 19.5m @ 7.4 g/t gold from 1.3 metres from PRAJ0006;
- 5.4m @ 37.6 g/t gold from 2.5 metres from PRAJ0009 (including 1.0m @ 189.0 g/t gold from 6.9 metres);
- 12.6m @ 3.6 g/t gold from 6.7 metres in PRAJ0005;
- 19.0m @ 2.3 g/t gold from 8.0 metres from PRAJ0022;
- 8.7m @ 4.6 g/t gold from 16.9 metres from PRAJ0025;
Multi-element analyses from all core sample holes from the Palokas project at Rajapalot (holes PRAJ0003 to PRAJ0025) shows consistently low uranium (weighted average through quoted intersections is 36ppm uranium and 5.2g/t gold) and high cobalt grades associated with gold mineralization.
A 16km drill program was completed during 2017/18 winter. Highlights include 31.7 metres @ 8.4 g/t gold from 244.1 metres, including 10.9 metres at 21.0 g/t gold from 252.2 metres in PAL0093 at the Raja prospect located 1.3km SW of Palokas
Sampling is coincident with and immediately up-dip from modelled VTEM geophysical conductors and strong and consistent IP chargeability anomalies through an area with <1% outcrop, and forms part of a 3.5 kilometre target horizon between basaltic and quartzitic rocks. The average depth of holes reported is 29 metres. The true thickness of the mineralized interval is interpreted to be approximately 80% of the sampled thickness. Drilling was performed with a Company-owned and operated, hand portable, low impact rig, below 2-5 metres of glacial till overburden in the vicinity of gold bearing glacial boulders and subcrop.
Fine disseminated gold mineralization at Palokas occurs within calcsilicate-biotite-tourmaline-pyrrhotite rocks in a contact zone between mafic rocks and relatively oxidized quartzites. The true thicknesses of the mineralized intervals is interpreted to be approximately 80% of the sampled thickness.
The discovery of highly significant cobalt enrichment associated with previously identified gold mineralization at the Rajapalot project followed an extensive multi-element drill core re-assay program, followed by a mineralogical QEMSCAN study led by the Geological Survey of Finland (“GTK”) to determine mineral association. Numerous cobalt-rich intervals have been identified which mirror and extend gold mineralized zones.
Cobalt is a key component in the cathode of most lithium-ion batteries and is considered crucial in the switch to electric mobility and greener generation and storage of energy.As a result, the cobalt price has escalated approximately 300% within the past two years. Cobalt is on the European Commission’s critical raw minerals list, delivering a strong mandate to discover and develop local and ethically produced supply alternatives.
With the world’s largest cobalt refinery, Freeport Cobalt, located only 400 kilometres south in Kokkola, Rajapalot is ideally positioned to play an important role as a potential sustainable and transparent supplier to the fast-growing European lithium ion battery supply chain.
- Significant assays received to date include (full assay table shown in Table 1):
- PAL0075: 10.8 metres @ 1,299 ppm Co, 6.2g/t Au (8.7g/t AuEq) from 8.7 metres
- PRAJ0009: 30.8 metres @ 525 ppm Co, 7.1g/t Au (8.2g/t AuEq) from 2.5 metres
- PRAJ0006: 19.5 metres @ 696 ppm Co, 7.1g/t Au (8.5g/t AuEq) from 1.3 metres
- PRAJ0107: 15.0 metres @ 602 ppm Co, 8.7g/t Au (9.9g/t AuEq) from 24.7 metres
- Combined gold-cobalt mineralized intersections display increased widths and often show better continuity.
- Mineralogical studies on selected Rajapalot samples indicates that sulphide cobalt mineralization is hosted in cobaltite and cobalt pentlandite that are conventionally mined and processed in other deposits;
- Results indicate the cobalt has the potential to add significant value as a by-product. Results received to date show gold equivalent (“AuEq”) assays that incorporate cobalt are 20-30% higher than gold only (“Au”) assays;
- Finland is an attractive jurisdiction for the discovery and development of cobalt. Finland presently refines half of the world’s cobalt outside of China, relying on predominantly imported feedstock from a Chinese-owned mine in the Democratic Republic of Congo. A future domestic Finnish source of cobalt would satisfy the recent announcements by Finland and Sweden that the countries will work together on a traceable ledger for sustainable minerals, considered crucial for achieving climate goals.
Although the exploration focus will remain for gold at Rajapalot, cobalt adds significant value as a potential by-product with a 20-30% increase in calculated gold equivalent (“AuEq”) grade over gold (“Au”) grade when incorporating cobalt. Cobalt distribution is strongly correlated with gold. However, cobalt appears to be more widespread in and around gold intervals and grades appear more consistent than gold (Table 1, Figures 1, 2 and 3). Cobalt-only zones also form peripheral to the gold-bearing zones (i.e. PAL0048 7.9 m @ 1081 ppm cobalt and 0.1 g/t Au).
During October 2014 the Company announced results from preliminary metallurgical testing on drill core from the Palokas prospect at the Rompas-Rajapalot gold project in Arctic Finland by SGS Mineral Services UK in Cornwall. Excellent gold extraction results of between 95% and 99% (average 97%) were obtained by a combination of gravity separation and conventional cyanidation. Gravity extraction for the four composites responded well with 26-48% gold extraction. Leaching was performed on the pulverised and blended tailings from the three size fractions after gravity extraction. Samples tested are not classified as refractory. Metallurgical test work indicates gold recovery and processing are potentially amenable to conventional industry standards with a viable flowsheet which could include crushing and grinding, gravity recovery, and cyanide leaching with gold recovery via a carbon-in-pulp circuit for production of onsite gold doré.
The host sequence comprises an isoclinally folded package of amphibolite facies metamorphosed Paleoproterozoic rocks. This package can be divided into two parts. Sequence 1 is a siliciclastic, dolomitic carbonate and albite-altered metasedimentary sequence interpreted as forming in a platformal to continental margin setting. Sequence 2 is a metasedimentary sequence of pelitic turbidites, arkosic sands, carbonates, impure and pure quartzitic sandstones and sulphidic bituminous rocks. An unconformity between the two sequences is interpreted between the largely oxidised rocks of Sequence 1 and reduced rocks of Sequence 2. Mafic rocks, ranging from lava flows, volcaniclastic sediments to dykes and differentiated sills form up to 20 % of the total package. Rare, but significant magnetite iron formations up to 20 metres thick occur towards the top of Sequence 1.
Metamorphic grade is largely amphibolite facies throughout the project area, from near the greenschist-amphibolite facies boundary in the south with increasing grade towards the north into sillimanite stability field. Retrograde alteration to chlorite or epidote is relatively common adjacent to quartz veins and fractures. Tourmaline-bearing granitoids (ca. 1.8 Ga) are exposed within 3 kilometres to the north, and recent drilling at the Boardwalk prospect has revealed albitised granitoids and diorites of unknown age in the core of the project area.
Two distinct styles of gold mineralization dominate the Rajapalot area. The first, is a variably sulphidic iron formation, known as the “Palokas” style. This forms in the uppermost part of Sequence 1 within approximately 100 metres of the inferred unconformity. A largely retrograde mineral alteration assemblage includes chlorite, Fe-Mg amphiboles, tourmaline and pyrrhotite commonly associated with quartz veining. Subordinate almandine garnet, magnetite and pyrite occur with bismuth tellurides, scheelite, ilmenite and gold. Metallurgical testing at Palokas reveals the gold to be non-refractory and 95% pure (with minor Ag and Cu) with excellent recoveries by gravitational circuit with conventional cyanidation.
Gold mineralization uncovered in boulders and drilling at the “Boardwalk” prospect is a variant on the Palokas style – so far in drilling the main source of the boulders has not been discovered. However, zones up to 20 metres thick of anomalous gold in iron formations has been intersected (best intersection 1 metre @ 3.19 g/t Au from 32 metres in PAL0074). These zones only have trace chlorite, unlike the chlorite-magnetite-grunerite boulders which average 15.3 g/t Au (15 boulder and grab samples >0.1 g/t Au with a range of 0.18 – 221 g/t Au). Throughout the entire 10 x 10 kilometre Rompas-Rajapalot project area variants of this iron formation have been recorded, included in a drill section at South Rompas (some 8 km west of Palokas). The recently discovered iron formation host rocks supports the Homestake analogue recently reported by Mawson and demonstrates that the new interpretation of the lithogeochemistry with the airborne and ground magnetics is allowing the exploration footprint to broaden.
The second style of gold mineralization at Rajapalot (known as “Rumajärvi”-type) is characteristically associated with muscovite and/or biotite, in a diverse range of fabrics. Gold grades of more than 1 g/t Au are associated with pyrrhotite and contained within muscovite-biotite schists, muscovite and biotite-bearing albitic granofels and brecciated, variably micaceous albitic rocks. Magnetite is a common mineral, but not a necessity for anomalous gold grades. The host rocks are grey to white owing to their reduced nature and may be enclosed by light pink to red calcsilicate-bearing albitites. To date, Rumajärvi style has been intersected a little lower in Sequence 1 than the iron formation-hosted gold, but given the apparent strong structural control on grade, stratigraphic constraints may not be relevant.
Structural interpretation of new drill core indicates a previously unrecognized early folding event causing regional inversion of the stratigraphy during F1 isoclinal folding. This effectively doubles the available volume of reactive rocks to the hydrothermal gold mineralizing event. The recognition of this early F1 folding event combined with our geophysics data has been instrumental in creating targets along strike to the east and of the Raja prospect and to the northeast of Palokas. Drilling continues at these targets.
Much of the mineralization at Rajapalot consists of sulphide (pyrrhotite>>pyrite), magnetite, biotite, muscovite and chlorite hydrothermal mineral assemblages hosted in predominately grey albitites and muscovite-biotite schists. Iron-and magnesium-rich hydrothermally altered sulphidic rocks are abundant at Palokas, and form local pods or structurally controlled void infills at other prospects. Textures range from veined albitic granofels through fractured and brecciated to locally schistose. Veining and fracture fill minerals include pyrrhotite, magnetite and magnetite-pyrrhotite (+/- quartz). Local retrograde chlorite after biotite and vein-controlled chlorite+/- tourmaline and magnetite are also present. Preliminary hand-held XRF analysis confirms the presence of associated scheelite and molybdenite, the former visible under UV light as tiny veinlets and disseminations. The iron-rich nature of the mineralized rocks is a common theme in either the oxide or sulphide form, with a variably sulphidic and chloritic overprint. The alteration is clearly post-metamorphic, reduced, and most likely driven by granitoid intrusions. Chlorite is regarded as the lowest temperature silicate mineral with gold, structurally controlled in apparent spatial association with quartz and/or K-feldspar veins. Altered rocks enclosing the mineralized package contain locally abundant talc and tourmaline.
The geophysical search for Palokas and Rumajärvi styles sulphidic gold mineralization under thin glacial cover is improving quickly with the knowledge gained in each drill program. A combination of ground magnetics, induced polarization and electromagnetic/resistivity methods can effectively target both styles in the near surface (less than 100 metres). The recording of magnetic susceptibility and conductivity in all drill core is aiding the development of a 3D target model. Combined with base of till assays, areas of Au-Bi-Te anomalism can be identified for either additional geophysics, or drill testing.
Exploration for Palokas and Rumajärvi style gold prospects is no longer just restricted to the Rajapalot area. Recognition of both Sequence 1 and 2 as a package enclosing the 6 km long vein-hosted Rompas Au-U system increases the search space for the pyrrhotite-gold systems. The geochemical characteristics of the iron formations and their low-iron equivalents are not only present in the southern drill section at South Rompas, but have more than 50 km of strike length in Rompas-Rajapalot. It is the interaction of this reactive rock package with late, sulphur- and gold-bearing hydrothermal systems driven by ca. 1.8 Ga granitoids, that now form the most highly prospective targets away from the Rajapalot area.