Norsk versjon
	THE ORE DATABASE
	Deposit Area 1114 - 005
	(Last updated 18.jul.2023)

Importance

Public:

Not Assessed (reg. 18.02.2015)

Economical:

Not classified/evaluated

Mineralization

	Era:	Proterozoic	Period:	Neoproterozoic
	Dating:		Method:
	Genesis:	Hydrothermal vein	Form:	Irregular
	Main texture:	Structureless	Min. distribution:	Disseminated (<20 % ore minerals)

Main grain size:

Very unevenly grained

Main alteration:

	Strike/Dip:	305 / 80	Direction:
			Plunge:

Stratigraphic classification of host rock

Era:

Proterozoic

Period:

Mesoproterozoic

	Province:	South Norwegian Basement Province
	Geotec.unit:	Agder Complex
	Tectonic complex:	Sirdal Magmatic Belt
	Igneous complex:

Group:

Formation:

Mineralogy

	Relationship	Mineral	Amount
	Gangue mineral	Feldspar	Major mineral (>10%)
	Gangue mineral	Quartz	Major mineral (>10%)
	Gangue mineral	Biotite	Subordinate mineral (1-10%)
	Ore mineral	Molybdenite	Major mineral (>10%)
	Ore mineral	Scheelite	Subordinate mineral (1-10%)
	Ore mineral	Wolframite	Subordinate mineral (1-10%)

Lithology:

	Relationship	Rock	Origin
	Host rock	Biotite-hornblende gneiss	Intrusive
			Metamorphic facies :Amphibolite
	Host rock	Granite	Intrusive Original rock :Granite
			Metamorphic facies :Amphibolite

Structures

	Location:	Type:	Orientation(360 gr.):	Relation to min.:
	Host rock	Mineral banding	Strike/Dip :305 / 80	Pre-mineralisation ;...Effect :None

Information(s) in free text format

Free text

Hovland gruve er anlagt som en grunnstoll til W-Mo mineraliseringene i Sandnesskjerpene. De ligger langs den vestligste av de to subparallelle, NV-SØ orienterte mineraliserte sonene i Ørsdalen. Denne sonen er ca. 300 m lang og domineres av rikere mineralisering av molybden enn wolfram. Mo-mineraliseringene finnes som regel i granittt. Stollen har retning 55 grader og er drevet inn fra østsida av Grubetjørna. Den er vannfylt og ved inngangen dominerer porfyrisk granitt. Molybdenglans finnes langs stikk og som aggregater i granitt på tippen som utgjør ca. 600 kbm.

Bibliography:

From NGU's Reference Archive:

Heier, K. , 1954

	En geologisk undersøkelse av bergartene og malmforekomstene i Ørsdalen.

;Norges geologiske undersøkelse;FAGRAPPORT;Bergarkivet; No.BA 3938;135 pages

	Abstract:
	Rapporten er et hovedfagsarbeide og gir en bred utredning om Ørsdalsfeltets geologi. Følgende tema blir spesielt behandlet: - Petrografi. - Granitisering. - Malmgeologi. - Metamorfose. - Tektonikk. I rapportteksten er det en rekke fotografier, diagrammer, figurer og analyser.

Heier, Knut , 1956

	The geology of the Ørsdalen district, Rogaland, S. Norway.

;Norsk geologisk forening;TIDSSKRIFTARTIKKEL;Norsk geologisk tidsskrift; No.36 (3/4);167-211 pages

Abstract:

The tungsten and molybdenite deposit in the area has been dealt with earlier by the author; this paper deals with the general geology, petrology and rock metamorphism of the region. After the regional geology has been briefly described, the paper deals with the petrographical classification of the rocks exposed. These are amphibolites and two types of quartzo-feldspathic gneisses. Then follows a short description of the rock structures. It is shown how a heavy folding of orogenic nature has effected all the rocks and it is concluded that they must have reacted to the folding in a plastic way. A chapter where the metasomatic processes are discussed follows next and the conclusions reached are that the one kind of the gneisses may have originated through metasomatism of anorthositic rocks while strong evidence is that the other has been formed by replacement of amphibolites and related rocks. The metasomatism is belived to be synkinematic. The metamorphism is dealt with at some length and it is shown that all the rocks must once have belonged to granulite facies, which is also the PT conditions during which the metasomatism took place. Later a retrograde metamorphism has affected the rocks within certain zones which are believed to represent tectonical zones of weakness. A map showing the metamorphic situation of the area is presented and here a division of the rocks into three groups according to differences in metamorphism is undertaken. These are: high amphibolite facies (including granulite facies), low amphibolite facies, epidote amphibolite- and greenschist facies. It is shown how a division of the rocks into one of these three groups can be based upon variations in the minerals of the quartzo-feldspathic gneisses alone. The paper ends with some considerations upon the relative age of the Telemark and Egersund formations of pre-Cambrian rocks. Based on the

Heier, Knut , 1955

	The Ørsdalen tungsten deposit.

;Norsk geologisk forening;TIDSSKRIFTARTIKKEL;Norsk geologisk tidsskrift; No.35 (1-4);69-85 pages

Abstract:

The general geology and the type of mineralization are shortly discussed, and the different ore minerals occurring are described. The minerals show a zoning opposite to what is generally considered the rule. Special attention is directed to the tungsten minerals (wolframite and scheelite) and it is shown how wolframite is altered into scheelite. This process is ascribed to a Ca metasomatism, probably brought about by late hydrothermal solutions reacting with the already formed wolframites. Experimental work has proved this reaction to go rather quickly. In the field this process is connected in time with other processes traceable in the history of the rocks. The formation of the ore is very briefly discussed.

Olerud, Svein , 1980

	Geologiske og geokjemiske undersøkelser rundt Ørsdalen W-Mo forekomst.

;Norges geologiske undersøkelse;FAGRAPPORT;NGU-rapport; No.1750/51A;34 pages

Abstract:

Rapporten tar for seg de geologiske og geokjemiske forhold i området rundt Ørsdalen W-Mo forekomst og behandler resultatene av geokjemiske undersøkelser i et 50 kv. kilom. stort område rundt forekomsten. W-Mo i forekomsten er knyttet til bånd i en antiform struktur, men mineraliseringen er uregelmessig og vanskelig å følge. De kjente forekomster er rike nok til å være økonomisk interessante men reservene er for små. Mellom Schånnings gruve og stoll1 er et 400 m høyt parti som ikke er undrsøkt. Videre boring her vil bli vanskelig og kostbar p.g.a utilgjengelig terreng. Geokjemien i området gir utslag for de kjente forekomster pluss noen anomalier utenom. Oppfølgingen av anomaliene ga negativt resultat. W i bekkesedimenter viste seg å være et bra alternativ til tungmineralvasking.

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

Sandberg, P.C. 1953. Oversikt over utfølrte arbeider og foreløpige undersøelser. BV rapprt 7135, 5s.

Bjørlykke, H. 1953. Ørsdalen Wolframforekomst. BV Rapport 1142, 9s.

Bjørlykke, H. 1952. Bergverksrapporter Mjåvassknuden, Ørsdalen. BV Rapport 7163, 6s.

Limyr, O. 1983. Eksploration works 1982. Fallverk A7S Norske Fina A/S. BV Rapport 1134, 18s.

Fieldsamples

	Sample No.	Sample type	Miscellanrous
	JS-W2106	Dump	Sampler :J.S.Sandstad/...Stored :Løkken/...Size(kg) :2 Comment :Molybdenite veinlets/aggregates in granite in contact with amphibolite No. of registrated element analyses = 1

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

Name of Locality : Sandnesskjerpene synk

(Object Id : 1114,005,01,00)

---

Location

County :

Rogaland (11)

Municipality :

Bjerkreim (1114)

Map 1:50000:

Ørsdalsvatnet (1312-3)

Map 1:250000:

Mandal

Marking point:

(Unavailable)

Commodity

	Main Type:	Ferroalloys (Cr,Ni,Co,V,Mo,W)	Sub Type:	Molybdenium
			Element(s):	Mo W

Production

	Activity:	Test mining	Reserves:
	Prod. method:	Underground mining	Production:
	Prod. status:		Volume of dump:

Information(s) in free text format

Free text

Sandnessynken ligger ca. 50 m NV for og ca. 35 m høyere i terrenget enn stollinngangen til Hovland gruve. Den er en liten vannfylt og har sidevegger på 3 x 1,5 m. Den er drevet langs kontakten mellom grovkornet granitt i nordøst og migmatittisk biotitt-gneis i sørvest. Relativt rik molybdenglans-mineralisering finnes som aggregater, disseminert og på stikk i granitten.

Fieldsamples

	Sample No.	Sample type	Miscellanrous
	JS-W2105	Dump	Sampler :J.S.Sandstad/...Stored :Løkken/...Size(kg) :2 Comment :Molybdenite dissemination/aggregates in granite No. of registrated element analyses = 1

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

Name of Locality : Sandnesskjerpene SØ

(Object Id : 1114,005,02,00)

---

Location

County :

Rogaland (11)

Municipality :

Bjerkreim (1114)

Map 1:50000:

Ørsdalsvatnet (1312-3)

Map 1:250000:

Mandal

Marking point:

Longitude:

6.4349260

Latitude:

58.6733400

EU89-UTM Zone 32

(Coordinates IS confirmed)

X-coord:

351259 m.

Y-coord:

6506523 m.

Commodity

	Main Type:	Ferroalloys (Cr,Ni,Co,V,Mo,W)	Sub Type:	Molybdenium
			Element(s):	Mo W

Production

	Activity:	Test mining	Reserves:
	Prod. method:	Open pit mining	Production:
	Prod. status:		Volume of dump:	100 m3

Information(s) in free text format

Free text

Dette er en ca. 18 m, 3-4 m bred og opptil 3 m høy dagskjæring som ligger ca. 50 m sørøst for Sandnessynken. Middel- til grovkornet granitt dominerer i skjerpet. Molybdenglans opptrer disseminert, i aggregater og i kvartsårer/linser i granitt. En prøve av denne inneholder 4,5 % Mo.

Fieldsamples

	Sample No.	Sample type	Miscellanrous
	JS-W2107	Dump	Sampler :J.S.Sandstad/...Stored :Løkken/...Size(kg) :2 Comment :Molybdenite, strong dissemination/aggregates in granite No. of registrated element analyses = 1

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

Name of Locality : Sandnesskjerpene NV

(Object Id : 1114,005,03,00)

---

Location

County :

Rogaland (11)

Municipality :

Bjerkreim (1114)

Map 1:50000:

Ørsdalsvatnet (1312-3)

Map 1:250000:

Mandal

Marking point:

Longitude:

6.4320170

Latitude:

58.6744230

EU89-UTM Zone 32

(Coordinates IS confirmed)

X-coord:

351095 m.

Y-coord:

6506650 m.

Commodity

	Main Type:	Ferroalloys (Cr,Ni,Co,V,Mo,W)	Sub Type:	Molybdenium
			Element(s):	Mo W

Production

	Activity:	Pitting	Reserves:
	Prod. method:		Production:
	Prod. status:		Volume of dump:

Information(s) in free text format

Free text

Dette er et mindre skjerp ca. 150 m NV for Sandnessynken.

---

Analyse Results

from

Deposit Area 1114 - 005 Hovland

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-W2105	Dump	503	115	12	11	18	1.1	4.0
JS-W2106	Dump	129	341	23	33	51	.5	1.0
JS-W2107	Dump	62	180	15	8	7	.3	-1.0

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

Sample No.	Pt#	Pd#	As*	Cd*	Ba*	Mo*	Sn*	Sb*	Bi*
JS-W2105	-5.0	3.0	0	.8	340	13900.00	2	0	1
JS-W2106	-5.0	1.0	0	1.0	520	9170.00	7	0	1
JS-W2107	-5.0	1.0	1	1.4	400	45400.00	5	0	0

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

Sample No.	Se*	Ga*	Ge*	In*	S%	V*	Cr*	Mn*	Fe%
JS-W2105	3.00	10.80	0.08	0.09	1.95	41	17	478	4.32
JS-W2106	3.00	32.20	0.21	0.21	1.06	224	79	1635	10.50
JS-W2107	17.00	20.90	0.21	0.18	3.21	81	13	868	5.85

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

Sample No.	Th*	U*	W*	Rb*	Sr*	Y*	Zr*	Nb*	Ta*
JS-W2105	0.47	0.60	75	94.5	38.0	6.9	102	9.20	0.35
JS-W2106	2.36	0.90	212	170.0	281.0	59.7	99	19.10	0.94
JS-W2107	2.44	1.10	19	121.0	54.2	77.1	177	21.60	0.60

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

Sample No.	Cs*	La*	Ce*	Li*	Be*	Na*	Mg*	Al*	P*
JS-W2105	4.95	12.70	24.70	32	2	8200	3700	27000	310
JS-W2106	15.30	59.10	140.50	41	9	27500	21500	80800	2470
JS-W2107	2.12	43.80	110.00	35	4	14400	5600	43800	880

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

Sample No.	K *	Ca*	Sc*	Ti*	Te*	Hf*	Re*	Tl*
JS-W2105	11200	6500	4.10	3500	0.71	3.40	0	1
JS-W2106	17900	36000	27.70	11050	0.37	2.90	0	1
JS-W2107	13600	12600	14.00	6220	1.22	4.80	0	1

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The fact sheet was created on 20.01.2025

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

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