Haukiaho - Overview
The Haukiaho property is located near Posio in northern Finland and is related to the Koillismaa Layered Igneous Complex (KLIC), which is one of the numerous mafic layered intrusions emplaced in the Fennoscandian Shield some 2.4-2.5 Ga ago. The igneous stratigraphy of the KLIC is generally divided into some 50–250 metre thick marginal series hosting very extensive but generally low-grade nickel-copper-platinum group elements-gold mineralisation and up to 3,000 metre thick layered series. The lower and middle portions of the layered series are composed mainly of norites and gabbronorites and the upper portion comprises leucogabbros, anorthosites and vanadium-enriched magnetite gabbros, which can reach up to 200 metres in thickness (Figure 1). The Syöte and Porttivaara vanadium projects of Vulcan as well as the past Mustavaara vanadium mine, which is located only some 5 kilometres south-east of the Haukiaho mineralisation, are related to the magnetite gabbro horizons.
The marginal series related nickel-copper-platinum group elements mineralisation in the Haukiaho area was initially mapped and drilled (16 holes) by Outokumpu in 1960’s. From early 1980’s till early 1990’s Outokumpu explored the marginal series for platinum group elements by completing detailed geological mapping, sampling and ground geophysical surveys. The GTK carried out an extensive exploration programme including also diamond drilling during 1998-1999. North Atlantic Natural Resources (NAN) acquired GTK’s properties in 2000 and continued exploration activities till 2002. The work comprised ground geophysics, low-altitude airborne geophysical survey contracted by Fugro Ltd and diamond drilling. Also a metallurgical flotation test by Lakefield Research Ltd of Canada was completed for NAN. The work by the GTK and NAN resulted in the delineation of the Haukiaho nickel-copper-platinum group elements-gold mineralisation related to the marginal series of the Kuusijärvi block. Follow-up resource drilling on the property was conducted by the GTK still in 2004 (Figure 2).
The Haukiaho mineralisation is hosted mainly by pyroxenitic and gabbroic cumulates of the marginal series. Mineralisation is steeply dipping to north-north-east and is generally 15-40 metres thick. Continuations along strike and dip are very extensive and consistent. The mineralisation occurs as disseminated sulphides and only very few narrow massive sulphide veins have been encountered. Pyrrhotite, pentlandite, chalcopyrite, and also pyrite in lesser amount, are the main sulphide minerals.
Best drill results are:
- R404 16.0 m interval from 58.40 m @ 0.20% Cu, 0.15% Ni, 0.34 g/t Pt, 0.95 g/t Pd
- R404 12.0 m interval from 129.00 m at 0.25% Cu, 0.18% Ni, 0.28 g/t Pt, 0.93 g/t Pd
The average metals concentrations and ratios for the Haukiaho mineralisation are 0.24% nickel, 0.36% copper, 0.97g/t 2PGE+Au, Pd:Pt = 2.64 and Pt:Au = 1.38. The figures are based on 116 drill core samples, which returned more than 0.7 g/t Pt+Pd+Au.
A scoping flotation test by Lakefield was done from a 50 kilogram sample collected from large mineralised boulders on the Haukiaho property. The feed grade was 0.25% nickel, 0.37% copper, 0.57 g/t palladium, 0.23 g/t platinum and 0.31 g/t gold. The best result of the test series returned 64% nickel and 89% copper recoveries into a concentrate grading 5.0% nickel and 9.7% copper. The lower total nickel recovery was a result of the presence of non-sulphide nickel, which will not be recovered by flotation. Precious metals recoveries were 80.1% for platinum, 79.8% for palladium and 65% for gold.
No JORC compliant resource estimate is available on the Haukiaho property. The GTK assessed the potential for an open pittable resource by modelling the Haukiaho mineralisation as a tabular sheet with a 20 metre average thickness, 3,000 metre strike length and 150 metre vertical depth along the dip. Total tonnage of this model was 27 Mt when specific gravity of 3.00 was applied. Grade estimate of 0.24% nickel, 0.36% copper, 0.21 g/t platinum, 0.55 g/t palladium and 0.22 g/t gold was made using a 0.7 g/t Pt+Pd+Au cut-off value.
Figure 1. Geological maps of the Koillismaa Layered Igneous Complex. Location of the marginal series related Haukiaho Ni-Cu-PGE-Au mineralization is shown as a black circle on the south-western portion of the Kuusijärvi block (figure from Alapieti and Kärki, editors, 2005).
Figure 2. Geological map and drill hole locations on the Haukiaho property (figure from Iljina et. al., 2005, geology after Räsänen et al 2005). Claim boundaries relate to GTK tenements expired in December 2005. Kylylahti Copper Oy’s claim reservation covers the same area with further extension to south on the Archaean granitoid gneiss area.
Figure 3. Cross-section of the Haukiaho mineralisation. The location of section is shown in Figure 1 (Iljina et. al., 2005).