Laivakangas-S - Gold Database

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Name	Laivakangas-S	DATA UPDATED	9.2.2006
Alternative names	Kauniinhaudanmalmi
LOCATION
Geological domain	Svecofennian	Belt	Raahe-Haapajärvi
Site photo		Regional map
Map sheet	243209
Northing (kkj)	7159890	Easting (kkj)	2527930
Latitude	64.53613N	Longitude	24.57821E
Municipality	Raahe
Nearest town, roads	16 km S from Raahe, 50 km SW from Oulu. A sealed road 8 km from the area, a gravel road to the area.
MINING
Exploration licence no	3181/1, 3463/1, 3649/2, 6122/1, 6571/1–5, 7979/3–7	Mining concession no
Present holder	Nordic Mines AB (2005–)
Previous holders	Outokumpu Oy (1980's), Endomines Oy (–2005)
Mine photo 1		Mine photo 2
Mine photo 3		Mine photo 4
Status of development	Prospect
When mined
Resources	Indicated 0.05 Mt @ 10 ppm + inferred 0.2 Mt @ 5 ppm Au (cutoff 2 ppm) [8].
Deposit size (Mt)	0.25	Reference (size)	[8]
Total in-situ gold (kg)	3500	Reference (in-situ Au)	[8]
Total gold production (kg)		Reference (gold prod)
Production of other metals
Extent of mineralisation
Lodes
Best sections	3.5 m @ 5 ppm Au [1].
EXPLORATION
Discovery year	1982
Discovery	By Outokumpu: The first indication was an sample from a glacial erratic boulder found by an amateur prospector on 1980 [2,4].
Exploration history	Outokumpu Oy (1980's) [2,4,8]: bedrock mapping, till and stream sediment geochemistry, survey of glacial erratic boulders, till stratigraphy, magnetic and IP ground survey, diamond drilling, pilot-plant tests.
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		Explor site photo 2
Geophysical response
Drilling	Outokumpu: 18 diamond-drill holes [8].
Elements analysed
Primary dispersion
Secondary dispersion
Primary anomaly fig 1		Secondary anomaly fig 1
Primary anomaly fig 2		Secondary anomaly fig 2
Primary anomaly fig 3		Secondary anomaly fig 3
Primary anomaly fig 4		Secondary anomaly fig 4
Primary anomaly fig 5		Secondary anomaly fig 5
Economic evaluations	A resource estimate for Endomines by GTK in 2001 [8].
Exploration geologist in charge	Outokumpu: Esa Sandberg, Endomines Oy: Jaakko Liikanen.
ORE
Siting of gold
Fineness
Major opaques	Arsenopyrite, loellingite [4].
Minor opaques	Gold
Gangue
Ore miner. photo 1		Ore miner. photo 5
Ore miner. photo 2		Ore miner. photo 6
Ore miner. photo 3		Ore outcrop photo 1
Ore miner. photo 4		Ore outcrop photo 2
Ore composition	Diamond-drill core [1]: 5.5 ppm Au, 0.590 ppm Ag, 580 ppm As, <0.5 ppm B, 566 ppm Ba, 38.8 ppm Bi, 11 ppm Co, 184 ppm Cu, 5 ppb Hg, 1 ppm Mo, 28 ppm Ni, <2 ppm Pb, 147 ppm Rb, 1690 ppm S, <0.2 ppm Sb, 0.88 ppm Se, 344 ppm Sr, 0.700 ppm Te, 5.8 ppm Th, 2.4 ppm U, 120 ppm V, 77 ppm W, 44 ppm Zn; 65.9% SiO2, 0.49% TiO2, 12.4% Al2O3, 5.90% Fe2O3, 3.40% MgO, 4.30% CaO, 2.76% Na2O, 3.48% K2O, 0.13% P2O5, 0.62% LOI.
Enriched elements	Au, Ag, As, Bi, K, Rb, S, Te, W [1].
Ore fluid
Stable isotopes
Pb isotope data
GEOLOGY
Geological setting	The mineralisation is in a sequence of Palaeoproterozoic metavolcanic rocks intruded by 1.89–1.87 dykes, sills and plutons [3,4,7]. It is in mafic metavolcanic rock and the felsic and intermediate intrusions surrounding the volcanic unit [8].
Major host rocks	Tonalite [1].
Minor host rocks	Mafic metavolcanic rock, granite [8].
Intrusives	A 1.89–1.88 Ga synorogenic tonalite and a younger granite hosting the mineralisation [3,4,7].
Regional geol map 1		Outcrop photo 1
Regional geol map 2		Outcrop photo 2
Local geology map 1		Outcrop photo 3
Local geology map 2
METAMORPHISM
Metamorphic history
Metamorphic grade	Amphibolite facies [2,3,4].
Metamorphic mineral assemblage
Metamorph photo 1		Metamorph photo 2
STRUCTURE
Structural style	Brittle-ductile [2,3].
Closest major shear	The mineralisation is located between NW-trending major (>100 km long) shear zones of the Raahe-Ladoga suture zone [5].
Controlling structure	A set of parallel, E- or ENE-trending, subvertical shear zones [8].
Deformation history
Ore fabric
Veins	Auriferous arsenopyrite-quartz veins in the narrow shear zones [4].
Structure photo 1		Vein photo 1
Structure photo 2		Vein photo 2
Structure photo 3		Vein photo 3
ALTERATION
General alteration
Proximal alteration
Intermediate alteration
Distal alteration
Zonation figure		Prox alteration photo 1
Alteration photo 1		Prox alteration photo 2
Alteration photo 2		Intermed alteration photo
Alteration photo 3		Distal alteration photo 1
Post-mineralisation modifications
TIMING
GENETIC MODEL	Features described in [2,3,4] indicate an orogenic "mesothermal" mineralisation formed under amphibolite-facies PT conditions.
GENETIC TYPE	Orogenic 'mesothermal'.
References 1. 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. 2. Korkalo, T. 1991. Kaivoslain 19 pyk. mukainen tutkimustyöselostus: Raahen kaupunki: Pirttihaudankangas, Siljanneva, Pirttivaara, Kauniinhaudansuo. Outokumpu Oy, Report 080/2441, 2432/TTK/91. 3 p. (in Finnish) 3. Mäkelä, M., Sandberg, E., Rantala, O. 1988. Proterozoic, gold-bearing vein occurrences associated with the granitoids in western Finland. In: A. D. T. Goode et al. (comp.) Bicentennial Gold 88, Melbourne, Victoria, May 16–20, 1988: Extended abstracts. Poster programme. 1. Geological Society of Australia. Abstracts Series 23, 153–155. 4. Mäkelä, M., Sandberg, E. & Rantala, O. 1988. Geochemical exploration of gold-bearing veins associated with granitoids in western Finland. In: ed. D. R. MacDonald & K. A. Mills Prospecting in Areas of Glaciated Terrain – 1988: Papers presented at the Eighth International Symposium on Prospecting in Areas of Glaciated Terrain, Halifax, Nova Scotia, August 28 – September 3, 1988: Canadian Institute of Mining and Metallurgy. 255–270. 5. Korsman, K., Koistinen, T., Kohonen, J., Wennerström, M., Ekdahl, E., Honkamo, M., Idman, H. & Pekkala, Y. (eds.) 1997. Suomen Kallioperäkartta = Berggrundskarta över Finland = Bedrock map of Finland 1:1 000 000. Geol. Surv. Finland. 6. Mäkelä, M. 1984. Raahen Laivakankaan kvartsi-arseenikiisukultaesiintymä. Unpublished MSc thesis. University of Turku. 105 p. (in Finnish) 7. Korsman, K. (ed.) & Glebovitsky, V. (ed.) 1999. Raahe-Ladoga Zone structure-lithology, metamorphism and metallogeny: a Finnish-Russian cooperation project 1996–1999. Map 2: Metamorphism of the Raahe-Ladoga Zone 1:1000000. Geol. Surv. Finland. 8. Parkkinen, J. 2001. Quality control of mineral resource estimates: Laivakangas, Hosko, Kuivisto E, Other, Osikonmäki, Pirilä, Housuvaara, Pahkalampi. Geol. Surv. Finland, Report. 27 p.
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