Fact Sheet for <b>Occurence 4227

					Norsk versjon
	THE ORE DATABASE
	Occurence 4227 - 025 Benkehei
	(Object Id: 5074) (Last updated: 13.02.2024)

Location

County:

Agder

Municipality:

Kvinesdal (4227)

Map 1:50000:

Fjotland (1412-3)

Map 1:250000:

Mandal

Coordinate system:

EU89-UTM Zone 32

East:

388456 m.

North:

6504119 m.

Longitude:

7.0771030

Latitude:

58.6629390

Show on map

Resource

	Resource Type:	Ferroalloys (Cr,Ni,Co,V,Mo,W)	Resource Subtype:	Molybdenium
			Element(s):	Mo

Importance

Raw material meaning:

Not Assessed (reg. 18.02.2015)

Resources and production

	Activity:	Mining	Reserves:	23 thousand tons
	Operating method:	Underground mining	Historical production:	13,6 thousand tons

Products

Element/product Crude ore grade or quality Reg. date

MoS2 0.25-0.3 % 13.02.2024

Operations

From - To Activity Comments

1916 - 1918 Test mining Company/Institution :Benkehei grube Co A/S

Herman Jensen, eier av Næs Mineralmølle i Tvedestrand startet driften i 1916

Mineralization

Genesis: Form:

Main texture: Min. distribution:

Main grain size: Main alteration:

Strike/Dip: Direction:

Plunge:

Stratigraphic classification of host rock

Era: Period:

Province:

Geotec.unit:

Tectonic complex:

Igneous complex:

Group: Formation:

Mineralogy

Relationship Mineral Amount

Gangue mineral Quartz Major mineral (>10%)

Gangue mineral Biotite Subordinate mineral (1-10%)

Gangue mineral Feldspar Subordinate mineral (1-10%)

Ore mineral Molybdenite Major mineral (>10%)

Structures

Location: Type: Orientation(360 gr.): Relation to min.:

Host rock Hydrothermal vein Strike/Dip :0 / 30 Syn-mineralisation ;...Effect :Controls

Information(s) in free text format

Free text

Benkehei ligger i en brattskrent øst for Knaben sentrum og ca. 300 m nord for det vannfylte dagbruddet til Knaben II. Forekomsten består av et nordre og søndre felt, og koordinatene er angitt til gruveinngangen ved nordre felt. Arbeidene startet i 1916 og ble avsluttet i 1919 etter at totalt skal være utdrevet ca. 14 t malm med 0,25-0,3 % MoS2 (Bugge 1963). I nordre felt et det to gruveåpninger som fører inn til et bergrom som skråner ned mot øst og er ca. 30 m langt N-S. Molybdenmineraliseringene er godt synlig i pilarer i bergrommet. Molybdenglans finnes i og langs 2- 10 cm tykke kvarts±feltspat-årer og som tynne linser i rødlig porfyrisk granitt. To til tre subparalle Mo-førende kvartsårer finnes i de 2-2,5 m høye pilarene. Granitten ligger i slire-båndet gneis (‘tigergneis’).

Bibliography:

From NGU's Reference Archive:

Müller, Axel; Henderson, Iain; Jourdan, Charles; Slagstad, Trond , 2016

Mineralization styles and formation temperatures of the Knaben molybdenum deposits, southern Norway

;Norges geologiske undersøkelse;RAPPORT;NGU-rapport; No.2015.030;59 pages

Abstract:

The report documents the lithologies and molybdenite mineralization exposed in underground mines of the Knaben molybdenum (Mo) mining district in Kvinesdal, Vest-Agder, SW Norway. Scanning electron microscope cathodoluminescence (SEM-CL) and trace element analyses of quartz by laser ablation inductively coupled mass Spectrometry (LA-ICP-MS) were performed on 37 quartz and quartz-bearing samples in order to better understand the P-T conditions during magma emplacement and Mo-mineralization.

Bugge, Arne , 1963

Norges molybdenforekomster.

;Norges geologiske undersøkelse;TIDSSKRIFTARTIKKEL;NGU; No.217;1-134 pages

Abstract:

The ore fields and individual deposits which are mentioned in the text are shown on the map, figure 2. For those areas where the deposits lie so close together that they cannot be shown separately on this map, detail maps have been drawn on larger scales. In the descriptions there will also be found special maps covering the most important molybdenum areas. An index of the deposits which are mentioned is arranged both alphabetically and according to the numbers on the map. The majority, including the most important, of the ore deposits in Southern Norway lie within a marked zone, which is shown on the map, figure 3. At varying periods of time different metals have characterised the long zone of ore deposits: titanium in the southwest, then molybdenum in the area from Gursli to Knaben, copper and molybdenum in Telemark, silver, zinc and lead from Kongsberg eastwards, and further to the east, molybdenum again. From the map, figure 4, it can be seen that the most important groups of deposits are situated to both sides of the granite-gneiss area of the mountanious region of Southern Norway and that they lie in migmatised gneisses along the southwest side and in the schists and quartzites of the Telemark supracrustal suite along the northeast side.

Holmsen, T. W. , 1961

Rapport over molybdenglansforekomster i Vestlandske distrikt i området Vest-Agder fylke samt herredene Lund og Sokndal i Rogaland.

;Norges geologiske undersøkelse;FAGRAPPORT;Bergarkivet; No.BA 7513;178 pages

Abstract:

Rapporten er ordnet i tre deler. Del 1 gir oversikt over alle mutede skjerp i området (side 4-106). Del 2 gir driftsberetninger hentet fra Norges Bergverksdrift for de skjerp hvor det har vært undersøkelsesarbeid eller regulær drift (side 107-135). Del 3 gir tittel med korte sammendrag av rapporter fra de aktuelle steder som er beskrevet (side 136-158). Side 158-176 består av kartbilag i M 1:50 000. Tittel forts.: ... Rogaland fylke.

Fieldsamples

Sample No. Sample type Miscellanrous

JS-W2115 Bedrock

Sampler: J.S.Sandstad/...Stored: Løkken/...Size(kg): 2

Comment: Molybdenite, along quartz-pegmatite in porphyric granite

No. of registrated element analyses = 1

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

Analyse Results

from

Deposit Area 4227 - 025 Benkehei

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-W2115 Bedrock 946 25 6 2 4 2.2 3.0

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

Sample No. Pt# Pd# As* Cd* Ba* Mo* Sn* Sb* Bi*

JS-W2115 -5.0 -1.0 1 1.2 150 18200.00 1 0 4

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

Sample No. Se* Ga* Ge* In* S% V* Cr* Mn* Fe%

JS-W2115 9.00 4.63 0.09 0.06 1.42 22 7 176 1.04

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

Sample No. Th* U* W* Rb* Sr* Y* Zr* Nb* Ta*

JS-W2115 7.42 1.30 7 56.5 36.8 11.0 56 4.80 0.46

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

Sample No. Cs* La* Ce* Li* Be* Na* Mg* Al* P*

JS-W2115 0.89 14.70 30.50 12 1 4400 800 13300 150

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

Sample No. K * Ca* Sc* Ti* Te* Hf* Re* Tl*

JS-W2115 7300 2200 1.20 760 1.53 1.70 0 0

	Element/product	Crude ore grade or quality	Reg. date
	MoS2	0.25-0.3 %	13.02.2024

From - To	Activity	Comments
1916 - 1918	Test mining	Company/Institution :Benkehei grube Co A/S
		Herman Jensen, eier av Næs Mineralmølle i Tvedestrand startet driften i 1916

	Genesis:		Form:
	Main texture:		Min. distribution:

	Province:
	Geotec.unit:
	Tectonic complex:
	Igneous complex:

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

	Location:	Type:	Orientation(360 gr.):	Relation to min.:
	Host rock	Hydrothermal vein	Strike/Dip :0 / 30	Syn-mineralisation ;...Effect :Controls

Sample No.	Sample Type	Cu*	Zn*	Pb*	Co*	Ni*	Ag*	Au#
JS-W2115	Bedrock	946	25	6	2	4	2.2	3.0

Sample No.	Pt#	Pd#	As*	Cd*	Ba*	Mo*	Sn*	Sb*	Bi*
JS-W2115	-5.0	-1.0	1	1.2	150	18200.00	1	0	4

Sample No.	Se*	Ga*	Ge*	In*	S%	V*	Cr*	Mn*	Fe%
JS-W2115	9.00	4.63	0.09	0.06	1.42	22	7	176	1.04

Sample No.	Th*	U*	W*	Rb*	Sr*	Y*	Zr*	Nb*	Ta*
JS-W2115	7.42	1.30	7	56.5	36.8	11.0	56	4.80	0.46

Sample No.	Cs*	La*	Ce*	Li*	Be*	Na*	Mg*	Al*	P*
JS-W2115	0.89	14.70	30.50	12	1	4400	800	13300	150

Sample No.	K *	Ca*	Sc*	Ti*	Te*	Hf*	Re*	Tl*
JS-W2115	7300	2200	1.20	760	1.53	1.70	0	0