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Modified: 17.08.2009

Saattopora - Gold Database

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Name Saattopora DATA UPDATED 30.1.2008
Alternative names  
Deposit summary SAATTOPORA, in the Central Lapland greenstone belt, was mined during 1988-1995 when 6279 kg gold and 5177 t copper was produced from the deposit. There is no information about the remaining resource. It is a Palaeoproterozoic orogenic gold deposit with an anomalous metal association (Au-Cu). It is hosted by albitised intermediate tuffite and phyllite, which obviously formed the locally most competent rock units during mineralisation. The three main lodes are E-W trending and comprise swarms of N-S trending quartz-carbonate veins formed under brittle deformation. The deposit is in the major, here E-W trending, Sirkka Shear Zone. Mainly free native gold in quartz-carbonate veins and in their immediate wallrock, chiefly associated with quartz, carbonates and sulphides.
LOCATION
Geological domain Lapland Belt Central Lapland
Site photo saattopora_airphoto_thumb Regional map central_lapland_deposits_th
Map sheet 274104
Northing (kkj) 7522830 Easting (kkj) 2517400
Latitude 67.79153N Longitude 24.40803E
Municipality Kittilä
Nearest town, roads 40 NW km of Kittilä, 200 km NNW of Rovaniemi. 10 km to a sealed road, a gravel road to the mine site.
MINING
Exploration licence no   Mining concession no 2288/1a, 1b
Present holder Belvedere Resources (2006–)
Previous holders Outokumpu Oyj (1974–2006)
Mine photo 1 saattopora_pit1992_thumb Mine photo 2 saattopora_pit1998a_thumb
Mine photo 3 saattopora_pit1998b_thumb Mine photo 4 saattopora_airphoto2_th
Status of development Open pit and underground, mining ceased.
When mined 1988–1995
Resources Original resource estimate (1988) was 0.68 Mt @ 3.6 ppm Au and 0.3% Cu [9,10,11].
Deposit size (Mt) 2,163 Reference (size) [1,2]
Total in-situ gold (kg) 6300 Reference (in-situ Au) [1,2]
Total gold production (kg) 6279 Reference (gold prod) [1,2]
Production of other metals 5177 t Cu [1,2]
Extent of mineralisation The two main lodes are up to 20 wide and 250–400 m long [5,6,20].
Lodes Two main lodes, the northern A lode and the southern B lode, both dipping to the N [2,5,6,7,14,21], and a smaller C lode [8].
Best sections 15 m @ 6 ppm Au, 0.3 Cu [20].
EXPLORATION
Discovery year 1985
Discovery By Outokumpu [2,5,6,9,10,11,14,20]: A base metal mineralisation adjacent to the gold deposit was discovered 1970 by bedrock mapping and diamond drilling, and the gold deposit was detected in 1985 by reanalysing Au of the earlier drill core.
Exploration history Outokumpu 1960's to 1995 [2,5,6,9,10,11,13,20]: Started as base metal exploration [2,11,12,20] which continued as Au exploration in the 1980's: bedrock mapping, till stratigraphy and geochemistry, trenching, diamond, percussion and RC drilling, ground magnetic, slingram and VLF surveys, mineralogical and geochemical studies.
Section figure 1   Plan figure 1  
Section figure 2   Plan figure 2  
Section figure 3   Plan figure 3  
Trench fig 1   Trench fig 4  
Trench fig 2   Trench fig 5  
Trench fig 3   Trench fig 6  
Explor site photo 1 saattopora_earlymining_th Explor site photo 2  
Geophysical response No response detected [2,5,6,9,10,11,13].
Drilling Outokumpu (1964–1994) [2,5]: Saattopora and the adjacent areas: diamond drilling 58.7 km, percussion drilling 27.2. km, RC drilling 0.7 km. Diamond drilling at site in 20x20 m grid which was filled by 5x5 m grid of percussion drilling during mining [6].
Elements analysed Au, Ag, Co, Cu, Ni, Pb, Zn by AAS, S by Leco (by Outokumpu). By GFAAS: Ag, Au, Co, Cu, Mo, Ni, Pb, Te, Zn, by fire assay: Au, by ICP: Ag, Al, As, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, La, Li, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Sc, Si, Sr, Th, Ti, V, Y, Zn [7].
Primary dispersion A distinct Au anomaly to the south of the base-metal deposit, i.e. enveloping the gold deposit [12].
Secondary dispersion  
Primary anomaly fig 1   Secondary anomaly fig 1  
Primary anomaly fig 2   Secondary anomaly fig 2  
Primary anomaly fig 4   Secondary anomaly fig 4  
Primary anomaly fig 5   Secondary anomaly fig 5  
Primary anomaly fig 3   Secondary anomaly fig 3  
Economic evaluations Feasibility study by Outokumpu 1988–1989 [5].
Exploration geologist in charge Outokumpu: Tuomo Korkalo.
ORE
Siting of gold Mainly free native gold in quartz-carbonate veins and in their immediate wallrock, chiefly associated with quartz, carbonates and sulphides, locally also with U-Th oxides [10].
Fineness <1% Ag, traces of Cu and As [2,10].
Major opaques Pyrite, pyrrhotite [2,10].
Minor opaques Chalcopyrite, gersdorffite, rutile, pentlandite, tucholite, uraninite, bismuthite, niccolite, tellurides and gold [2,10,12,14].
Gangue Quartz, Fe dolomite, ankerite, albite, tourmaline [2,10,12].
Ore miner. photo 1 saattopora_ore_th Ore miner. photo 5  
Ore miner. photo 2   Ore miner. photo 6  
Ore miner. photo 3   Ore outcrop photo 1 saattopora_prox_thumb
Ore miner. photo 4   Ore outcrop photo 2 saattopora_ore_th
Ore composition Average mined ore: 3.29 ppm Au, 0.28% Cu [2].
15 analyses of ore: 45.8% SiO2, 10.24% Al2O3, 0.11% MnO, 7.33% CaO, 0.26% K2O, 0.033% Cr2O3, 7.76 ppm Au, 190 ppm Co, 4890 ppm Cu [10].
Diamond-drill core, A-lode [7]: 9.10 ppm Au, 0.021 ppm Ag, 28 ppm As, 621 ppm B, 84 ppm Ba, 0.2 ppm Bi, 88 ppm Co, 1980 ppm Cu, 7.0 ppb Hg, <1.0 ppm Mo, 346 ppm Ni, <2 ppm Pb, 13 ppm Rb, 45800 ppm S, 0.2 ppm Sb, 1.16 ppm Se, 57 ppm Sr, 1.40 ppm Te, <0.5 ppm Th, 9.9 ppm U, 270 ppm V, 27 ppm W, 23 ppm Zn, 51 ppm Zr; 33.8% SiO2, 0.79% TiO2, 7.37% Al2O3, 16.8% Fe2O3, 6.80% MgO, 10.3% CaO, 3.31% Na2O, 0.36% K2O, 0.06% P2O5, 6.43% LOI.
Diamond-drill core, B-lode [7]: 2.90 ppm Au, 0.302 ppm Ag, 570 ppm As, 216 ppm B, 167 ppm Ba, 2.7 ppm Bi, 248 ppm Co, 8350 ppm Cu, 20.0 ppb Hg, 2.0 ppm Mo, 1000 ppm Ni, 14 ppm Pb, 17 ppm Rb, 64300 ppm S, 0.4 ppm Sb, 6.60 ppm Se, 52 ppm Sr, 1.80 ppm Te, 4.8 ppm Th, 22.9 ppm U, 130 ppm V, 7 ppm W, 53 ppm Zn, 67 ppm Zr; 31.8% SiO2, 0.44% TiO2, 7.02% Al2O3, 17.3% Fe2O3, 6.52% MgO, 10.2% CaO, 2.84% Na2O, 0.30% K2O, 0.034% P2O5, 10.1% LOI.
Ore composition table 1 Click here Ore composition table 2  
Enriched elements Au, Ag, As, B, Bi, CO2, Cu, S, Se, Te, U, W [2,7].
Ore fluid  
Stable isotopes Carbonates in ore: δ18O = +12.19 – +12.44 per mill, δ13C = -7.68 – -6.87 per mill [16]. Carbonates in alteration halo: δ18O = +12.63 – +13.18 per mill, δ13C = -7.22 – -6.85 per mill [16]. Carbonates in ore: δ18O = +12.19 – +12.44 per mill, δ13C = -7.68 – -6.87 per mill [16]. Carbonates in unaltered mafic rock: δ18O = +12.10 per mill, δ13C = -6.87 per mill [16]. δ34S = -8.7 – +4.0 per mill in sulphides in the area; this range also includes the syngenetic base-metal deposit [12].
Pb isotope data [8]: Mantle-derived lead? Sulphides from Au concentrate give scattered Pb-Pb ages of 1907–1985 Ma. Linear Pb-Pb ages from sulphides and carbonates give 1894±46 Ma.
GEOLOGY
Geological setting The ore is chiefly hosted by a sequence of intensely altered, partially volcanogenic, metasedimentary rocks (graphitic phyllites) and equally altered, metapyroclastic rocks (intermediate to mafic tuffs and tuffites) which at Saattopora, due to their early alteration, are commonly called albitites [2,3,5,10,12,21]. Footwall: komatiite, hanging wall: graphitic phyllite [10]. The rock sequence is part of the >2050 Ma Savukoski Group of the Palaeoproterozoic Central Lapland Greenstone Belt [4,21].
Major host rocks Intermed., albitised metasedimentary and -pyroclastic rocks [2,5,12,].
Minor host rocks Metakomatiites [2,12,14].
Intrusives Dolerites which predate all alteration and mineralisation [12].
Regional geol map 1 central_lapland_deposits_th Outcrop photo 1  
Regional geol map 2 harrilommol_saattopora_geology_th Outcrop photo 2  
Local geology map 1 saattopora_map_thumb Outcrop photo 3  
Local geology map 2  
METAMORPHISM
Metamorphic history Metamorphic peak during D2, thrusting during D3 was at least partly post-peak, late metamorphic [23].
Metamorphic grade Lower- to mid-greenschist facies [3].
Metamorphic mineral assemblage Metakomatiites: talc-chlorite ± carbonate [12].
Dolerites: albite-actinolite-epidote-titanite [12].
Phyllites: quartz-albite-chlorite ± biotite, sericite, graphite [12].
Metamorph photo 1   Metamorph photo 2  
STRUCTURE
Structural style Brittle(-ductile) [2,3,12,14].
Closest major shear The Sirkka Line shear and thrust zone which is here E-W trending and about 250 m wide [2,4,10,14].
Controlling structure The gently southward dipping thrust, the Sirkka Line and its subsidiary, parallel brittle-ductile structures [2,4,10,19].
Deformation history Rifting during 2.5–1.9 Ga, compression from about 1.9 Ga [14,19]. Two major stages, the pre-D1 and D1 of the regional deformation history, recorded in the area; the former is related to N- to NW-directed thrusting and the latter to strike-slip movements along the faults [15]. Three major stages of deformation, D2 has produced the presently dominant foliation, D3 is related to tectonic movement from S to N; these all are postdated by <1.77 Ga NW- and NE-trending faults [19]. The Saattopora area is transected by late NE- and N-S trending shear and fault zones [20].
Ore fabric Massive, intensely brecciated [2,3,12].
Veins A few millimetres to several metres thick quartz-carbonate veins; these are chiefly N-S trending, but there also are E-W trending, conjugate(?), veins with similar mineralogy as the N-S trending veins [2,10,14,20,21]. The auriferous veins are tension cracks opened during folding [19]. Abundant calcite veins in the hangingwall tuffite [20]. The auriferous veins are undeformed, hence probably related to the rergional D3 stage of deformation [22].
Structure photo 1 saattopora_ore_th Vein photo 1 saattopora_oresample_1_th
Structure photo 2 saattop_oreveins_in_albitisedrock1_th Vein photo 2  
Structure photo 3 saattop_oreveins_in_albitisedrock2_th Vein photo 3  
ALTERATION
General alteration [2,3,12,14]: Two major stages of alteration:
1. Albitisation and part of carbonation may have preceded gold mineralisation, taken place before regional deformation, as a synvolcanic, spilitic stage of alteration, related to the formation of the syngenetic base-metal mineralisation in the phyllites. Albitised zones are 1–90 m wide and threir lateral and vertical extents are several hundreds of metres [14].
2. Sericitisation, sulphidation and main carbonation, with formation of abundant quartz veins, are most probably related to the syn-peak metamorphic gold mineralisation.
Proximal alteration  
Intermediate alteration  
Distal alteration Metakomatiites: talc-chlorite-carbonate [12].
Zonation figure   Prox alteration photo 1 saattopora_prox_thumb
Alteration photo 1   Prox alteration photo 2  
Alteration photo 2   Intermed alteration photo  
Alteration photo 3   Distal alteration photo 1 saattopora_distal_thumb
Post-mineralisation modifications Heating related to postorogenic granites has reset U-Pb and Pb-Pb ages in monazite, rutile, thucolite and pyrrhotite [8].
TIMING Probably, during 1870–1900 Ma [8], from the following data: U-Pb concordia age for monazite and thucolite 1781±18 Ma and for rutile 1684±5 and 1707±8 Ma, Pb-Pb age for pyrrhotite 1662±5–1704±4 Ma; the post-1.87 Ga ages probably reflect post-mineralisation heating related to postorogenic granites [8]. Sulphides from Au concentrate give scattered Pb-Pb ages of 1907–1985 Ma [8]. Linear Pb-Pb ages from sulphides and carbonates give 1894±46 Ma [8].
GENETIC MODEL During mineralisation, the Au-bearing veins were preferably developed in the most compact lithological units, chiefly in albitised rocks [2,14]. Probably, albitisation predated gold mineralisation and produced competent units which were structurally favourable for gold mineralisation [3,14]. Precipitation of gold was probably induceed by fluid-rock (graphite) interaction, that caused changes in pH and fO2 of the fluid and fluid unmixing [14].
[17,18]: Palaeomagnetic indications from remanent magnetism suggest that the main alteration stage took place during 1880–1840 Ma.
GENETIC TYPE Orogenic References  
Alternative genetic type 1   References  
Alternative genetic type 2   References  

References

1. Anttonen, R. 1998. Personal communication 15/02/1998.
2. Korvuo, E. 1997. The Saattopora gold ore and the Pahtavuoma Cu-Zn-U occurrences in the Kittilä region, northern Finland. In: E. Korkiakoski & P. Sorjonen-Ward (eds) Ore deposits of Lapland in northern Finland and Sweden. Geol. Surv. Finland, Guide 43, 21–25.
3. Eilu, P. 1997. Orogenic lode-gold deposits: Notes to accompany samples from deposits located on the Fennoscandian Shield. University of Turku, Department of Geology and Mineralogy, Publication 35, 1st edition. 14 p
4. Lehtonen, M. I., Airo, M-L., Eilu, P., Hanski, E., Kortelainen, V., Lanne, E., Manninen, T., Rastas, P., Räsänen, J. & Virransalo, P. 1998. Kittilän vihreäkivialueen geologia. Lapin vulkaniittiprojektin raportti. Summary: The stratigraphy, petrology and geochemistry of the Kittilä greenstone area, northern Finland. A report of the Lapland Volcanite Project. Geol. Surv. Finland, Report of Investigation 140. 144 p.
5. Anttonen, R., Korkalo, T. & Oravainen, H. 1989. Lapin kultaa Saattoporan kaivoksesta. Summary: Gold from Lapland – Outokumpu Oy's Saattopora mine. Vuoriteollisuus 47, 104–108.
6. Wyllie, R. J. M. 1989. Saattopora. Outokumpu opens Lapland gold mine, first new Finnish mine in years. Engineering and Mining Journal, June 1989, 40–43.
7. Nurmi, P. A., Lestinen, P. & Niskavaara, H. 1991. Geochemical characteristics of mesothermal gold deposits in the Fennoscandian Shield, and a comparison with selected Canadian and Australian deposits. Geol. Surv. Finland, Bulletin 351. 101 p.
8. Mänttäri, I. 1995. Lead isotope characteristics of epigenetic gold mineralization in the Palaeoproterozoic Lapland greenstone belt, northern Finland. Geol. Surv. Finland, Bulletin, 381. 70 p.
9. Anttonen, R. 1992. Outokumpu's experiences from exploitation of gold ores. Bidjovagge Mine, Saattopora Mine. Geol. Surv. Finland, Report M10.2/-92/1. 5 p. (in Finnish)
10. Hugg, R. 1991. Saattoporan kultamalmiesiintymästä. Geol. Surv. Finland, Report M10.2/-92/1. 5 p. (in Finnish)
11. Korvuo, E. 1992. Saattoporan kaivos: Kaivospäätös ja sitä seuranneet toimenpiteet sekä malmivarat. Geol. Surv. Finland, Report M10.2/-92/1. 4 p. (in Finnish, 470 KB)
12. Lehtinen, M. 1987. Kittilän tutkimusalue: Saattopora. In: H. Papunen (ed.) Lapin vulkaniittien tutkimusprojekti. Loppuraportti. Dept of Geology, Univ. of Turku, Report. 463 p. (in Finnish)
13. Wennervirta, H. 1972. Moreenin pintatutkimus, Muusanlammet, Kittilä. Outokumpu Oy, Report 062/2741 07/HW/72. 2 p. (in Finnish)
14. Grönholm, P. 1999. The mesothermal Saattopora copper-gold deposit in the Palaeoproterozoic Central Lapland greenstone belt, Northern Finland. In: N.J. Cook and K. Sundblad (eds) Precambrian gold in the Fennoscandian and Ukrainian Shields and related areas. Gold ’99 Trondheim, Norway, 4–6 May 1999. Geol. Surv. Norway. Trondheim. p. 83.
15. Patison, N.L. & Oliver, N.H.S. 2001. Structural features associated with Palaeoproterozoic gold deposits in the Central Lapland Greenstone Belt, northern Finland. In: P.J. Williams (ed) 2001: A Hydrothermal Odyssey. May 17–19th, 2001, Townsville. Extended abstracts. EGRU and JCU. 162–163.
16. Hölttä, P. & Karhu, J. 2001. Oxygen and carbon isotope compositions of carbonates in the alteration zones of orogenic gold deposits in central Finninsh Lapland. Geol. Surv. Finland, Special Paper 31, 25–29.
17. Airo, M.-L., Mertanen, S. 2001. Magnetic signatures related to Precambrian greenstone-hosted Au mineralizations, northern Fennoscandia. In: Vietnam 2001: IAGA–IASPEI joint scientific assembly, 19–31 August 2001, Hanoi, Vietnam : abstracts. Hanoi: IAGA : IASPEI, 263.
18. Mertanen, S. 2001. Sekundääriset remanenssit kallioperän geologisten prosessien ilmentäjänä. Abstract: Secondary remanent magnetization reflecting the geological processes in bedrock. In: XX Geofysiikan päivät Helsingissä 15–16.5.2001. Geofysiikan Seura, Helsinki. 81–86.
19. Väisänen, M. 2002. Structural features in the central Lapland greenstone belt, northern Finland. Geol. Surv. Finland, Report K 21.42/2002/3. 20 p. (32.8 MB)
20. Korkalo, T. 2006. Gold and copper deposits in Central Lapland, northern Finland, with special reference to their exploration and exploitation. Acta Univ. Oulensis, A Scientiae Rerum Naturalium 461. 122 p.
21. Eilu, P., Pankka, H., Keinänen, V., Kortelainen, V., Niiranen, T. & Pulkkinen, E. 2007. Characteristics of gold mineralization in the greenstone belts of northern Finland. Geol. Surv. Finland, Special Paper 44, 57–106.
22. Patison, N.L. 2007. Structural controls on gold mineralisation in the Central Lapland Greenstone Belt. Geol. Surv. Finland, Special Paper 44, 107–124.
23. Hölttä, P., Väisänen, M., Väänänen, J. & Manninen, T. 2007. Paleoproterozoic metamorphism and deformation in Central Lapland, Finland. Geol. Surv. Finland, Special Paper 44, 7–5 6.
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