Piilola - Gold Database

Back to Gold map			Alphabetical list
Name	Piilola	DATA UPDATED	24.5.2007
Alternative names
Deposit summary	PIILOLA, in the central part of the Kuhmo greenstone belt, is an Archaean orogenic gold occurrence with no resource estimate available. It is hosted by mica schist in the main, N-S trending, shear zone of the greenstone belt.
LOCATION
Geological domain	Archaean	Belt	Kuhmo
Site photo		Regional map
Map sheet	441210
Northing (kkj)	7139600	Easting (kkj)	4456000
Latitude	64.35257N	Longitude	29.08592E
Municipality	Kuhmo
Nearest town, roads	35 km NW from Kuhmo. A sealed road adjacent to the area, 13 km from railway.
MINING
Exploration licence no	7659/1	Mining concession no
Present holder	OPEN FOR ACQUISITION
Previous holders	Geological Survey of Finland (GTK) (2003–2004)
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	The main lode and the Likasuo lode, 2 km apart [3].
Best sections	1 m @ 4.2 ppm, 4 m @ 3.5 ppm, 5.1 m @ 4.4 ppm Au [1], 1 m @ 7.5 ppm, 1m @ 6.6 ppm Au, 0.5 m @ 17.3 ppm Au [3]. Likasuo: up to 5 pppm Au per metre [3].
EXPLORATION
Discovery year	2003
Discovery	By GTK [1]: discovery of an outcrop of auriferous, arsenopyrite-rich, altered mica schist during the local exploration campaign.
Exploration history	GTK (2002-2005) [1,3]: glacial erratic boulder survey, bedrock mapping, low-altitude airborne magnetic, electric and radiometric survey, regional and local till geochemical survey, ground electromagnetic, magnetic and IP survey, diamond drilling.
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	A distinct positive chargeability anomaly (IP survey) due to rocks containing sulphide dissemination; within the anomaly, there is a negative apparent resistivity anomaly (IP survey) which is due to the gold-mineralised zone detected [1,3]. There are other similar anomalies in the claim area, which still (2006) aren't checked by drilling [1,3].
Drilling	GTK (2003-2004): 30 diamond-drill holes, total 2427 m [1,3].
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
Exploration geologist in charge	GTK: Kimmo Pietikäinen
ORE
Siting of gold
Fineness
Major opaques	Arsenopyrite [1].
Minor opaques	Pyrite [1].
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
Ore composition table 1		Ore composition table 2
Enriched elements	As, Au, S, Sb, Te [1].
Ore fluid
Stable isotopes
Pb isotope data
GEOLOGY
Geological setting	Mineralisation is in a contact zone ('quartz-sericite rock') between mica schists and metagreywackes of the Late-Archaean Kuhmo greenstone belt in the west and TTG granitoid greisses in the east [1].
Major host rocks	Mica schist [1].
Minor host rocks
Intrusives	Archaean TTG-series 2739–2697 Ga tonalites and granodiorites to the east and sanukitoidal granodiorites to the west of the supracrustal sequence of the greenstone belt; granitoid pegmatites within the mineralised zone,and Palaeoproterozoic NW-trending dolerites in the region [1,2].
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
Metamorphic mineral assemblage
Metamorph photo 1		Metamorph photo 2
STRUCTURE
Structural style
Closest major shear	A N-S trending, ductile, subvertical, several hundreds of metres wide shear zone = the main shear zone of the Kuhmo greenstone belt [2].
Controlling structure	Eastern magrin of the regional N-S trending shear zone [3].
Deformation history	At least, six deformation stages during the late Archaean and two deformation stages during the Palaeoproterozoic detected in the area; gold mineralisation is related to the Archaean late D3 and/or D4 stages; D2: 2850-2837 Ma, D3: 2701-2697 Ma, D4: peaked at 2657±32 Ma; age of D2 is probably 2820±15 Ma [2] or 2843±18 Ma [4].The latest deformation is manifested by NW-trending mylonitisation in Palaeoproterozoic dolerites [1].
Ore fabric
Veins	Late pyrite veins cut across the mineralisation [3].
Structure photo 1		Vein photo 1
Structure photo 2		Vein photo 3
ALTERATION
General alteration	Silicification, sericitisation [1]. Likasuo: grossular, wollastonite, vesuvianite [3].
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	Thin pyrite-rich veins cut across the minaralisation [1].
TIMING
GENETIC MODEL
GENETIC TYPE	Orogenic	References	[1]
Alternative genetic type 1		References
Alternative genetic type 2		References
References 1. Pietikäinen, K., Halkoaho, T., Hartikainen, A., Niskanen, M. & Tenhola, M. 2005. Itä-Suomen arkeeiset alueet II-hankkeen (2105000) toiminta vuosina 2001–2004 Kuhmon, Nurmeksen, Lieksan ja Hyrynsalmen alueilla. Geol. Surv. Finland, Report M19/4411/2005/1. 84 p. (in Finnish, 23.2 MB) 2. Luukkonen, E., Halkoaho, T., Hartikainen, A., Heino, T., Niskanen, M., Pietikäinen, K. & Tenhola, M. 2002. Itä-Suomen arkeeiset alueet -hankkeen (12201 ja 210 5000) toiminta vuosina 1992–2001 Suomussalmen, Hyrynsalmen, Kuhmon, Nurmeksen, Rautavaaran, Valtimon, Lieksan, Ilomantsin, Kiihtelysvaaran, Enon, Kontiolahden, Tohmajärven ja Tuupovaaran alueella. Geol. Surv. Finland, Report M19/4513/2002/1. 265 p. (in Finnish, 130 MB) 3. Pietikäinen, K., Hartikainen, A. & Niskanen, M. 2006. Tutkimustyöselostus Kuhmon kaupungin pohjoisosassa sijaitsevasta valtauksesta Piilola 1 (7659/1). Geol. Surv. Finland, Report M06/4412/2006/1/10. 12 p. (English summary, 5.9 MB) 4. Sorjonen-Ward, P. & Luukkonen, E.J. 2005. Archean rocks. In: Precambrian Geology of Finland – Key to the Evolution of The Fennoscandian Shield. Elsevier Science B.V., Amsterdam, 19–9 9.
Back to Gold map			Alphabetical list