Kokkokorpi - Gold Database

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Name	Kokkokorpi	DATA UPDATED	12.9.2008
Alternative names	Tipasjärvi 1
Deposit summary	KOKKOKORPI, in the NE part of the Tipasjärvi greenstone belt, is an Archaean orogenic gold occurrence or a deformed syngenetic (epithermal?) occurrence. Due to minor drilling no resource estimate is available. The occurrence is hosted by mica schist, related to quartz-tourmaline veins. Gold occurs closely associted with arsenopyrite.
LOCATION
Geological domain	Archaean	Belt	Tipasjärvi
Site photo		Regional map
Map sheet	4322 12
Northing (kkj)	7095550	Easting (kkj)	445780
Northing (Uni)	7097023	Easting (Uni)	3604811
Latitude	63.957264N	Longitude	29.1389E
Municipality	Sotkamo
Nearest town, roads	25 km SW from Kuhmo. A few hundred of metres to gravel road, 5 km from a sealed road.
MINING
Exploration licence no	8077/1	Mining concession no
Present holder	Silver Resources (2007–)
Previous holders	GTK (2006)
Infrastructure fig 1		Infrastructure fig 2
Claim fig 1		Claim fig 2
Mine photo 1		Mine photo 2
Mine photo 3		Mine photo 4
Status of development	Prospect
When mined
Resources
Deposit size (Mt)		Reference (size)
Total in-situ gold (kg)		Reference (in-situ Au)
Total gold production (kg)		Reference (gold prod)
Production of other metals
Extent of mineralisation
Lodes
Best sections	1 m @ 3.16 ppm Au [1].
EXPLORATION
Discovery year	2006
Discovery	Discover by GTK [1]: Several As- and Au-rich quartz-tormaline vein and breccia erratics were found in the region in 2005; this was followed by basal till and bedrock surface sampling in profiles which indicated a, at least, 2 km long As-Au-Te anomaly in bedrock. Then the As-Au-Te anomaly was drilled and one Au-rich zone detected at a shallow depth [1].
Exploration history	GTK (2004–2006) [1]: glacial erratic survey, bedrock mapping, basal till and bedrock surface geochemical survey, diamond drilling, high-density low-altitude airborne radiometric, magnetic and electromagnetic survey (flight altitude 30 m, line distance 50 m).
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	GTK (2005–2006): 10 diamond-drill holes, total 969.8 m [1].
Elements analysed	ICP-AES (aqua regia leach): Ag, Al, As, B, Ba, Be, Ca, Co, Cr, Cu, Fe, K, La, Li, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Sc, Sr, T, V, Y, and Zn; Au and Te by GFAAS [1].
Primary dispersion	Arsenic and tellurium anomalies in bedrock relate to the gold-mineralised domain [1].
Secondary dispersion	Combined As-Au-Te anomaly in basal till seems to best indicate the location of gold-mineralised domain in bedrock [1].
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
Exploration geologist in charge	GTK: Aimo Hartikainen
ORE
Siting of gold	Gold is closely associated with arsenopyrite [1].
Fineness
Major opaques	Arsenopyrite, pyrrhotite [1].
Minor opaques	Ilmenite, chalcopyrite [1].
Gangue	Quartz, tourmaline, scheelite [1].
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
Ore composition table 1
Enriched elements	As, Au, S, Sb, Te [1].
Ore fluid
Stable isotopes
Pb isotope data
GEOLOGY
Geological setting	Located in the NE, sedimentary rock dominated, part of the 2.79 Ga Tipasjärvi Greenstone Belt (TGB) which as a whole is characterised, in decreasing abundance, by mafic, ultramafic and felsic volcanic rocks clastic metasedimentary rocks and BIF [1]. The local sequence comprises alteranating bands/beds of mica schist, greywacke and conglomerate with minor intercalations of mafic volcanic rock and mafic dykes [1].
Major host rocks	Mica schist [1].
Minor host rocks
Intrusives	The greenstone belt rocks are bounded to the N and E by 2.70–2.68 Ga granite which crops out 1–2 km from the Kokkokorpi area [1]. Proterozoic dolerite dykes cut the local Archaean sequence [1].
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 [1].
Metamorphic mineral assemblages	Mafic volcanic rock: quartz-plagioclase-hornblende-biotite [1]. Sericite schist: quartz-muscovite-chlorite-staurolite [1]. Mica schist: quartz-plagioclase-biotite-chlorite ± garnet [1]
Metamorph photo 1		Metamorph photo 2
STRUCTURE
Structural style	Ductile [1].
Closest major shear
Controlling structure	None reported, but the occurrence is near the NE margin of a greenstone belt: this boundary may also be a shear zone [1].
Deformation history
Ore fabric	Auriferous quartz-tourmaline veins [1].
Veins
Structure photo 1		Vein photo 1
Structure photo 2		Vein photo 2
Structure photo 3		Vein photo 3
ALTERATION
General alteration
Proximal alteration	Mica schist: quartz-muscovite-biotite-chlorite-plagioclase-tourmaline-sulphides [1].
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
Genetic type	Orogenic ?	References	[1]
Alternative genetic type 1	Sungenetic deformed ?	References	[1]
Alternative genetic type 2		References
References 1. Hartikainen, A., Niskanen, M. & Pietikäinen, K. 2007. A research report of gold exploration concerning the claim Tipasjärvi 1 (register number 8077/1) in Sotkamo during years 2004-2006. Geol. Surv. Finland, Report M06/4322/2007/42. 27 p. (in Finnish, English summary, 16 MB)
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