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	THE ORE DATABASE
	Deposit 1636 - 015 Løkken
	(Object Id: 1636,015,00,00) (Last updated: 15.03.2024)

Products

	Element/product	Crude ore grade or quality	Reg. date
	Ag	19 ppm	28.06.2001
	Co	0,07 %	28.06.2001
	Cu	2,1 %	28.06.2001
	S	41,4 %	28.06.2001
	Zn	1,9 %	28.06.2001

Operations

	From - To	Activity	Comments
	1654 - 1844	Regular production	Company/Institution :Participantskap
			Mange forskjellige eierforhold
	1850 - 1891	Regular production
	1904 - 1987	Regular production	Company/Institution :Orkla Gruber
	1974 - 1980	Regular production	Company/Institution :Orkla Industrier AS
	1980 - 1987	Regular production	Company/Institution :Løkken Gruber A/S & Co

Mineralization

	Era:	Paleozoic	Period:	Ordovician
	Genesis:	Volcex	Form:	Ruler
	Main texture:	Massive	Min. distribution:	Massive (>50 % ore minerals)

Main grain size:

Fine grained (< 1 mm)

Main alteration:

Chloritisation

	Strike/Dip:	290 / 45	Direction:	295
			Plunge:	15

Stratigraphic classification of host rock

Era:

Paleozoic

Period:

Ordovician

	Province:	Caledonides
	Geotec.unit:	Trondheim Nappe Complex
	Tectonic complex:
	Igneous complex:

Group:

Løkken Ophiolite Complex

Formation:

Mineralogy

	Relationship	Mineral	Amount
	Gangue mineral	Quartz	Major mineral (>10%)
	Gangue mineral	Carbonate	Accessory mineral (<1%)
	Ore mineral	Pyrite	Major mineral (>10%)
	Ore mineral	Chalcopyrite	Subordinate mineral (1-10%)
	Ore mineral	Sphalerite	Subordinate mineral (1-10%)
	Ore mineral	Hematite	Accessory mineral (<1%)
	Ore mineral	Magnetite	Accessory mineral (<1%)
	Ore mineral	Tennantite	Accessory mineral (<1%)
	Ore mineral	Tetrahedrite	Accessory mineral (<1%)
	Ore mineral	Pyrrhotite	Accessory mineral (<1%)
	Ore mineral	Galena	Accessory mineral (<1%)
	Ore mineral	Bornite	Accessory mineral (<1%)

Lithology:

	Relationship	Rock	Origin
	Wall rock	Greenstone	Extrusive Original rock :Basalt
			Metamorphic facies :Greenschist
	Wall rock	Jasper	Sedimentary Original rock :Exhalite
			Metamorphic facies :Greenschist
	Wall rock	Vasskis	Sedimentary Original rock :Exhalite
			Metamorphic facies :Greenschist

Structures

	Location:	Type:	Orientation(360 gr.):	Relation to min.:
	Wall rock	Primary layering	Strike/Dip :290 / 45	Syn-mineralisation

Information(s) in free text format

Free text

The Løkken deposit in the Løkken ophiolite was the largest ophiolite-hosted VMS deposit (i.e. Cyprus type) in the world. It contained an original tonnage of about 30 Mt grading 2.3 % Cu, 1.8 % Zn, 0.02 % Pb, 16 g/t Ag and 0.2 g/t Au. About 24 Mt of the ore was mined over a period of 333 years (1654–1987). The massive sulphide ore consists predominantly of pyrite with subordinate chalcopyrite and sphalerite, whereas galena, magnetite, hematite and bornite are minor components locally and fahlore is the most important accessory phase. Quartz is the main non-sulphide, constituting 12–14 % of the ore. Due to deformation, the ore body is tectonically disrupted into one major and several smaller bodies. The total length of the ore body is about 4 km, the average width 150–200 m and the thickness about 50 m. This morphology can be ascribed to primary features such as subparallel faults at the seafloor, and an extensive, fissure-related hydrothermal vent system. Associated with the massive ore body is an extensive feeder zone system, present along the entire 4 km deposit. The feeder zone has pyrite, chalcopyrite and quartz as its main constituents, and accessory amounts of sphalerite, magnetite and iron oxides. The total width of the zone is about 100 m. Because of its high Cu-content, this part of the deposit was the first to be mined at Løkken.

Bibliography:

From NGU's Reference Archive:

Birketvedt, J. , 1921

	Geologiske beskrivelser av Løkken grubes kisforekomst, samt en bergteknisk beskrivelse av driften omkring Wallenbergs sjakt.

;NTH Bergavd.;AVHANDLING

Borchgrevink, O.F. , 1932

	Foredrag av O.F.Borchgrevink 19 september 1932: Noen detaljer fra driften ved Løkken grube.

;Norges geologiske undersøkelse;FOREDRAG; RAPPORT;Bergarkivet; No.BA 3697;8 pages

	Abstract:
	Rapporten er et nedskrevet foredrag fra 175-årsjubileet for bergmanns- undervisning. Først i foredraget nevnes kort om den historiske utvikling når det gjelder brytningsteknikk og utvinning, og om hvilke forbedringer som er gjort opp gjennom årene. Rapporten nevner kort de brytningsmetoder som er i bruk (1932), og kommer med et forslag til effektivisering av lading av salver.

Marlow, Wolmer , 1914

	Geologisk bergteknisk beskrivelse av Løkken Grube.

;NTH Bergavd.;AVHANDLING

Vokes, Frank M. , 1960

	Description of mines and deposits. Løkken pyrite mine (Orkla Grube- Aktiebolag).

;Norges geologiske undersøkelse;EKSKURSJONSGUIDE; TIDSSKRIFTARTIKKEL;NGU; No.212m;64-73 pages

Borchgrevink, O.F. , 1954

	Løkken verk 300 år - Orkla Grube-Aktiebolag 50 år.

;TIDSSKRIFTARTIKKEL;Teknisk ukeblad; No.101 (47);1011-1020 pages

Grenne, Tor , 1989

	Magmatic evolution of the Løkken SSZ Ophiolite, Norwegian Caledonides: relationships between anomalous lavas and high-level intrusions.

;Wiley;TIDSSKRIFTARTIKKEL;Geological journal; No.Vol. 24;251-274 pages

Abstract:

The Lower Ordovician Løkken ophiolite fragment shows a tripartite subdivision of its thick volcanic sequence into: (1) an Upper Volcanic Member (UVM) of transitional MORB/IAT character, comprising bastalts or, in a related, thrustbounded sequence, a bimodal basal-rhyolite assemblage; (2) a Middle Volcanic Member (MVM) derived from widely variable, generally MORB-related magmas; and (3) a Lower Volcanic Member (LVM) of N-type MORB basalts which locally passes into an underlying sheeted dyke complex. The UVM and LVM were fed from relatively deep-seated magma chambers, and lavas were erupted at moderate flow rates to form predominantly pillow lavas. The whole sequence is interpreted as having formed in a marginal basin setting. The MVM is characterized by abundant voluminous sheet basalts thought to have been erupted at high flow rates. The volcanites had their source, through extensive dyke swarms, in high-level magmas which intruded the sheeted dyke complex and parts of the LVM, possibly in a near-axial seamount setting. The magmas differentiated to form plagiogranitic melts, with a wide range of conjunctive, mafic to intermediate cumulates. This plutonic assemblage, possibly in crystal mush form, was subsequently intruded by new, mafic magma, leading partly to large-scale remelting or assimilation of cumulus phases. These processes are reflected in the MVM by common hybrid flows, as well as local intermediate lavas having the geochemical characteristics of cumulates, erupted during a period of intense faulting. Major tapping of the primary, mafic magma occurred toward the end of the period of MVM volcanism. A predominance of voluminous, apparently fluid, massive flows in the MVM is mainly ascribed to the shallow depth of magma reservoirs.

Vokes, Frank M. , 1995

	Geological factors influencing the utilization of the Løkken Cu-Zn-Fe-S deposit, Meldal. Foredrag v/ekskursjon til Løkken og Orkdal 16 september 1995.

;FOREDRAG; TIDSSKRIFTARTIKKEL;Det Kongelige Norske Videnskabers Selskabs Forhandlinger;179-190 pages

Grenne, T.; Grammeltvedt, G.; Vokes, F.M. , 1980

	Cyprus-type sulphide deposits in the western Trondheim District, central Norwegian Caledonides.

;Cyprus Geological Survey Department;ARTIKKEL;Ophiolites; Proceedings International Ophiolite Symposium, Cyprus; 1979.;727-743 pages

Grenne, T.; Vokes, F.M. , 1990

	Sea-floor sulfides at the Høydal volcanogenic deposit, central Norwegian Caledonides.

;TIDSSKRIFTARTIKKEL;Economic geology; No.85;344-359 pages

Abstract:

The Høydal volcanogenic massive sulfide deposit is associated with thick basaltic sheet flows toward the middle of a 1-2 km thick, low-metamorphic, inverted, Lower Ordovician ophiolitic volcanite sequence in the central Norwegian Caledonides, just east of the major (25+ million metric tons) orebody at Løkken. Høydal is one of the very few Scandinavian Caledonian strata-bound vocanogenic massive sulfide deposits which retains dominantly sea-floor depositional features, due to the minimal effects of later deformation and metamorphism. This study documents these features and compares them with those of recently formed and presently forming sea-floor sulfides.

References not to be found in NGU's Reference Archive.:

Grenne, T. 1989: The feeder-zone to the Løkken ophiolite-hosted massive sulfide deposit and related mineralization in the central Norwegian Caledonides. Econ. Geol 84, 2173-2195.

Name of Locality: Wallenberg shaft

(Object Id: 1636,015,01,00)

Location

County:

Sør-Trøndelag (16)

Municipality:

Meldal (1636)

Map 1:50000:

Løkken (1521-3)

Map 1:250000:

Trondheim

Coordinate system:

EU89-UTM Zone 32

East:

534080 m.

North:

6999655 m.

Longitude:

9.6757110

Latitude:

63.1246430

Show on map

Resource

	Resource Type:	Base metals (Cu,Zn,Pb,Fe sulphides, As,Sb,Bi,Sn)	Resource Subtype:	Copper
			Element(s):	Kis Cu Zn

Name of Locality: Astrup shaft

(Object Id: 1636,015,02,00)

Location

County:

Sør-Trøndelag (16)

Municipality:

Meldal (1636)

Map 1:50000:

Løkken (1521-3)

Map 1:250000:

Trondheim

Coordinate system:

EU89-UTM Zone 32

East:

532517 m.

North:

6999948 m.

Longitude:

9.6448010

Latitude:

63.1274170

Show on map

Resource

	Resource Type:	Base metals (Cu,Zn,Pb,Fe sulphides, As,Sb,Bi,Sn)	Resource Subtype:	Copper
			Element(s):	Kis Cu Zn

Information(s) in free text format

Free text

Fem prøver av massiv sulfidmalm ble innsamlet på nivå 810 m (under overflaten). Fire av disse er kobberkis-pyritt malm med lite sinkblende, og i gjennomsnitt inneholder de 3,6 % Cu og kun 0,12 % Zn. Alle prøvene er anriket på kobolt med i gjennomsnitt 757 ppm Co, og erytrin ble også observert i gruva under prøvetakingen.

Fieldsamples

	Sample No.	Sample type	Miscellanrous
	JS-L1901	Bedrock	Sampler: J.S. Sandstad/...Stored: Løkken/...Size(kg): 2 Comment: Massive pyrite-chalcopyrite ore No. of registrated element analyses = 1
	JS-L1902	Bedrock	Sampler: J.S. Sandstad/...Stored: Løkken/...Size(kg): 2 Comment: Massive pyrite-chalcopyrite ore No. of registrated element analyses = 1
	JS-L1903	Bedrock	Sampler: J.S. Sandstad/...Stored: Løkken/...Size(kg): 2 Comment: Massive pyrite-chalcopyrite-sphalerite ore No. of registrated element analyses = 1
	JS-L1904	Bedrock	Sampler: J.S. Sandstad/...Stored: Løkken/...Size(kg): 2 Comment: Massive pyrite-chalcopyrite ore No. of registrated element analyses = 1
	JS-L1906	Bedrock	Sampler: J.S. Sandstad/...Stored: Løkken/...Size(kg): 2 Comment: Massive pyrite+chalcopyrite+sphalerite ore No. of registrated element analyses = 1

NB! All analyse values are shown at the end of the printout.:

Name of Locality: Moen shaft

(Object Id: 1636,015,03,00)

Location

County:

Sør-Trøndelag (16)

Municipality:

Meldal (1636)

Map 1:50000:

Løkken (1521-3)

Map 1:250000:

Trondheim

Coordinate system:

EU89-UTM Zone 32

East:

531869 m.

North:

7000160 m.

Longitude:

9.6319940

Latitude:

63.1293770

Show on map

Resource

	Resource Type:	Base metals (Cu,Zn,Pb,Fe sulphides, As,Sb,Bi,Sn)	Resource Subtype:	Copper
			Element(s):	Kis Cu Zn

---

Analyse Results

from

Deposit Area 1636 - 015 Løkken

Element analyses

( *=parts pr. million, #=parts pr.billion, Negative values means below detection limit value.)

Sample No.	Sample Type	Cu*	Zn*	Pb*	Co*	Ni*	Ag*	Au#
JS-L1901	Bedrock	62400	777	184	1200	18	44.2	213.0
JS-L1902	Bedrock	40100	807	217	773	34	38.4	264.0
JS-L1903	Bedrock	14700	2770	298	295	31	17.3	322.0
JS-L1904	Bedrock	27500	297	211	1100	17	25.7	267.0
JS-L1906	Bedrock	9680	2700	406	417	66	19.1	340.0

------------------

Sample No.	Pt#	Pd#	As*	Cd*	Ba*	Mo*	Sn*	Sb*	Bi*
JS-L1901	-5.0	-1.0	349	6.2	60	54.70	1	2	5
JS-L1902	-5.0	1.0	450	6.1	70	67.00	1	4	6
JS-L1903	-5.0	1.0	517	15.6	20	44.50	0	5	4
JS-L1904	-5.0	-1.0	393	2.0	20	106.00	0	3	4
JS-L1906	-5.0	1.0	277	24.1	10	64.30	1	6	4

------------------

Sample No.	Se*	Ga*	Ge*	In*	S%	V*	Cr*	Mn*	Fe%
JS-L1901	123.00	3.23	0.71	0.68	10.00	55	8	154	36.50
JS-L1902	78.00	6.51	0.73	0.83	10.00	143	14	228	35.70
JS-L1903	35.00	1.55	0.50	0.58	10.00	55	15	153	33.10
JS-L1904	53.00	1.17	0.49	1.31	10.00	63	16	99	33.20
JS-L1906	34.00	1.62	0.42	1.18	10.00	16	25	214	30.30

------------------

Sample No.	Th*	U*	W*	Rb*	Sr*	Y*	Zr*	Nb*	Ta*
JS-L1901	0.07	0.40	-0	2.7	13.3	1.3	1	-0.10	-0.05
JS-L1902	0.06	1.80	-0	9.3	5.8	2.5	1	-0.10	-0.05
JS-L1903	0.02	1.50	0	1.2	1.8	0.8	1	-0.10	-0.05
JS-L1904	0.01	1.60	-0	1.4	1.4	0.5	1	-0.10	-0.05
JS-L1906	0.02	1.30	0	0.5	1.3	0.4	1	-0.10	-0.05

------------------

Sample No.	Cs*	La*	Ce*	Li*	Be*	Na*	Mg*	Al*	P*
JS-L1901	1.30	-0.50	0.77	1	-0	0	0	0	20
JS-L1902	3.29	0.90	1.52	1	-0	0	0	1	70
JS-L1903	0.16	-0.50	0.41	0	-0	0	0	0	120
JS-L1904	0.14	-0.50	0.16	0	-0	0	0	0	30
JS-L1906	0.06	-0.50	0.19	1	-0	0	0	0	30

------------------

Sample No.	K *	Ca*	Sc*	Ti*	Te*	Hf*	Re*	Tl*
JS-L1901	0	1	0.40	-0	4.47	-0.10	205	3
JS-L1902	0	0	0.50	0	3.09	-0.10	225	4
JS-L1903	0	0	0.10	-0	1.84	-0.10	67	8
JS-L1904	0	0	0.10	-0	1.97	-0.10	171	3
JS-L1906	0	0	0.10	-0	1.42	-0.10	61	2

---

The fact sheet was created on 10.11.2024

Questions or comments regarding the fact sheet can be emailed to: ressursdatabaser@ngu.no

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