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	MALMDATABASEN
	Forekomstområde 522 - 029
	(Sist oppdatert 13.mar.2024)

Betydning

Offentlig:

Internasjonal betydning (reg. 13.03.2023)

Økonomisk:

Kan være viktig , (Stadfestet 06.jan.2010 av Rolf Lynum)

Produkt

	Element/produkt	Gehalt/Kvalitet
	CO	0.02 %
	CU	0.12 %
	NI	0.28 %

Mineralisering

	Æra:	Proterozoikum	Periode:	Mesoproterosoikum
	Datering:		Metode:
	Genese:	Ortomagmatisk	Form:	Linse
	Hovedtextur:	Årenettverk	Min. fordeling:	Disseminert

Kornstørrelse:

Middelskornet (1-3 mm)

Hovedomvandling:

	Strøk/Fall:		Retning:
			Feltstupning:

Stratigrafisk klassifikasjon av vertsbergart

Æra:

Proterozoikum

Periode:

Mesoproterosoikum

	Provins:
	Geotek.enhet:
	Tektonisk complex:	Espedalen Complex
	Intrusivt komplex:

Gruppe:

Formasjon:

Mineralogi

	Relasjon	Mineral	Mengde
	Gangmineral	Pyroksen	Hovedmineral (>10%)
	Malmmineral	Magnetkis	Hovedmineral (>10%)
	Malmmineral	Kobberkis	Underordnet mineral (1-10%)
	Malmmineral	Pentlanditt	Underordnet mineral (1-10%)

Litologi:

	Relasjon	Bergart	Opprinnelse
	Vertsbergart	Gabbronoritt	Intrusiv Opprinnelig bergart :Gabbronoritt
			Metamorf fase :Amfibolitt
	Vertsbergart	Harzburgitt	Intrusiv Opprinnelig bergart :Peridotitt
			Metamorf fase :Amfibolitt

Opplysning(er) i fritekstformat

Fri tekst

The Espedalen Ni-Cu district is situated in an outlier of the Jotun Nappe Complex and consists of Proterozoic crustal rocks; mainly a high-grade anorthosite-gabbro-troctolite suite. Magmatic Ni-Cu sulphides have been mined in several periods in the region. Copper smelting is documented at Svatsum in 1665–1666 with description of ongoing mining of unknown duration. The first analysis and description of a new Ni-mineral, later named pentlandite, was reported from Espedalen by Scheerer (1845). The findings resulted in two mining periods of nickeliferous pyrrhotite (1846 to 1857 and 1874 to 1878) from Storgruva, Veslegruva and a number of smaller workings, making Espedalen one of the major mining districts at that time (up to 500 workers). An estimated total of about 50.000 tons of ore with 1.0 % Ni, 0.4 % Cu was produced. Modern exploration started in the late 1960s. Sulfidmalm and Norsk Hydro did extensive exploration until 1980. The latest period of exploration by Blackstone Ventures Inc. started in 2003 and has so far resulted in the discovery of two new deposits, Stormyra and Dalen. The inferred resources in the Stormyra deposit is 1.013 mill.t. with 1.09 % Ni, 0.48 % Cu and 0.04 % Co and at Dalen 4.625 mill.t. with 0.29 % Ni, 0.12 % Cu and 0.02 % Co. Drake refined the Mineral Resources at Stormyra (1.16Mt @ 1% Ni, 0.42% Cu & 0.04% Co) and Dalen (7.8Mt @ 0.28% Ni, 0.12% Cu & 0.02% Co) prospects in accordance with JORC (2012).

Litteraturfortegnelser:

Referanser som ikke finnes i NGU's Referansearkiv.:

Corfu, F., & Heim, M. 2014. Geology and U–Pb geochronology of the Espedalen Complex, southern Norway, and its position in the Caledonian nappe systems. Geological Society, London, Special Publications, 390(1), 223-239. https://doi.org/10.1144/jgs2019-010

Mansur, E.T., Slagstad, T., Dare, S.A.S. & Sandstad, J.S. 2023. Geology and sulphide geochemistry of the Ni-Cu-Co mineralisation of the Espedalen Complex, Norway: Constraints for the distribution of magmatic sulphides within a variably deformed anorthosite suite. Ore Geology Reviews 161.

Reddick, J., & Armstrong, T. 2009. Technical Report on Resource estimates for Ertelien, Stormyra and Dalen Deposits, Southern Norway. NI43-101 technical report.

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Faktaarket ble generert 18.05.2024

Spørsmål eller kommentarer vedrørende faktaarket kan mailes til: ressursdatabaser@ngu.no

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