Fact Sheet for Deposit Area 238

					Norsk versjon
	THE ORE DATABASE
	Deposit Area 238 - 015
	(Last updated 19.des.2022)

Name of Deposit Area : Nedre Gruvelia

(Object Id : 0238,015,00,00)

Location

County :

Akershus (02)

Municipality :

Nannestad (0238)

Map 1:50000:

Nannestad (1915-3)

Map 1:250000:

Hamar

Marking point:

Longitude:

10.8878390

Latitude:

60.1791050

EU89-UTM Zone 32

(Coordinates IS confirmed)

X-coord:

604720 m.

Y-coord:

6672854 m.

Commodity

	Main Type:	Base metals (Cu,Zn,Pb,Fe sulphides, As,Sb,Bi,Sn)	Sub Type:	Zinc
			Element(s):	Zn

Production

Activity:	Test mining	Reserves:
Prod. method:	Open pit mining	Production:
Prod. status:		Volume of dump:	200 m3

Importance

Public: Not Assessed (reg. 18.02.2015)

Economical: Minor interest , (Confirmed 26.aug.2021 by Jan Sverre Sandstad)

Mineralization

Era: Paleozoic Period: Permian

Dating: Method:

Genesis: Skarn formation Form: Lens

Main texture: Structureless Min. distribution: Semi-massive (20-50 % ore minerals)

Main grain size: Fine grained (< 1 mm) Main alteration: Skarn formation

Strike/Dip: 305 / 70 Direction:

Plunge:

Stratigraphic classification of host rock

Era: Paleozoic Period: Ordovician

Province: Oslo Region

Geotec.unit: Akershus Graben

Tectonic complex:

Igneous complex: Nordmarka-Hurdal Batholith

Group: Formation:

Mineralogy

Relationship Mineral Amount

Gangue mineral Pyroxene Major mineral (>10%)

Gangue mineral Feldspar Subordinate mineral (1-10%)

Gangue mineral Garnet Subordinate mineral (1-10%)

Ore mineral Sphalerite Major mineral (>10%)

Ore mineral Pyrite Subordinate mineral (1-10%)

Ore mineral Pyrrhotite Subordinate mineral (1-10%)

Ore mineral Chalcopyrite Accessory mineral (<1%)

Lithology:

Relationship Rock Origin

Wall rock Biotite hornfels Sedimentary
Original rock :Argillaceous sediment

Metamorphic facies :Contact

Wall rock hedenbergite skarn Sedimentary
Original rock :Limestone

Metamorphic facies :Contact

Information(s) in free text format

Free text

Gruva som er beskrevet av Ihlen (1978) ble ikke påvist ved befaringen in 2021, men en rekke mindre gruver og skjerp ble funnet i området. Ifølge Ihlen (1978) er malmen knyttet til 1-2 m mektige skarnsoner i en opprinnelig isoklinal foldet mellom-ordovicisk kalkstein. Skarnsonene er omgitt av biotitthornfels, og langs kanten av disse er hornfels omvandlet til diopsid-alkalifeltspatbergart. Sinkblende opptrer som disseminerte korn, årer, segregasjoner og tynne lag i hedenbergitt og hedenbergitt-granat skarn. Sinkmineraliseringen er meget uregelmessig og over store partier finnes bare magnetkis og svovelkis i skarn (Ihlen 1978). Driften i hovedforekomsten som ble befart i 2021 består av en 14 m lang dagskjæring med retning 215°. Innerst i skjæringen er blottet en 20-30 cm bred sone med tilnærmet massiv, finkornet sinkblende i hedenbergittskarn. Grågrønn, finkornet hornfels dominerer ellers i veggene i dagskjæringen.

Bibliography:

From NGU's Reference Archive:

Ihlen, Peter M. , 1978

Malmgeologisk undersøkelse og kartlegging av Kongen, Sulitjelma, Røros, Øvre og Nedre Grubelien og Dalstjern gruver i Elsjøfeltet.

;Norges geologiske undersøkelse;FAGRAPPORT;NGU-rapport; No.1575/16B;8 pages

Abstract:

I Elsjøfeltet kan tre typer kontakt-metasomatiske malmer skilles ut: 1) Sinkblende-magnetkis og sinkblende-magnetitt malmer, henholdsvis i hedenbergitt-granat og granat-epidot skarn i omvandlede 1-2 m tykke kalksteinslag 2) Sinkblende-magnetitt-blyglans-Bi-sulfosalter i granat-epidot skarn langs forkastninger i hornfelser. 3) Sinkblende-magnetkis i hedenbergitt-granat-skarn i omvandlede bitumenøse kalklinser. Marmor og skarlinser som opptrer i alunskifer fører assosiert en granat-grafitt skarn med relativt høyt uraninnhold. Til type 1 og 2 hører henholdsvis Dalstjern, Nedre og Øvre Grubelien gruver og Erdmann gruve. Til type 3 hører Kongen, Sulitjelma og Røros gruve. Den sistnevnte type er interessant m.h.p. store tonnasjer av lavprosentlige Zn-U malm. Type 1 og 2 har for små mektigheter og for uregelmessig fordeling av sinkblende til å bli betraktet som interessant.

Olerud, Svein , 1984

Metallogeny of the Elsjø area, northern Oslo Region, Norway.

;Norsk geologisk forening;TIDSSKRIFTARTIKKEL;Norsk geologisk tidsskrift; No.64 (4);325-334 pages

Abstract:

The Elsjø area is situated in the northern part of the Oslo Region and consists of a 2 km² inlier of Palaeozoic metasediments. Cambro-Ordovician shales and limestones are enclosed in Permian intrusives and are contact metamorphosed and altered by metasomatic processes. The present investigation has defined three mineralisation types of interest: The heavy-metal content of the Alum shale, sphalerite-bearing skarn lenses within the Alum shale and molybdenite mineralisation in the underlying Permian granites. The Alum shale of the Elsjø area has a maximum thickness of more than 150 metres as a result of overthrusting and folding during the Caledonian orogeny. The highest heavy-metal content is in Upper Cambrian strata. The greatest average content is in 10.6 m thick layer with 160 ppm U, 200 ppm Mo, 930 ppm V, 11.6 % C and 2.8 % S. The Alum shale also contains lenses of hedenbergite-garnet skarn lenses with sphalerite mineralisation; these are alteration products of marble lenses in the shale. Similar sphalerite-bearing skarn mineralisation is also found in other stratigraphic levels on shear zones. The Palaeozoic sedimentary rocks are underlain by three types of Permian granites. Molybdenite occurs as scattered disseminations in the phyllic alteration zones of the granite. Propylitic alteration is common in both the underlying intrusives and in the Palaeozoic sediments. The molybdenite mineralisation has similarities with porphyry molybdenum type occurrences, but can also be interpreted as a roof zone mineralisation in the granites.

Fieldsamples

Sample No. Sample type Miscellanrous

JS-OS2141 Bedrock

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

Comment :Semi-massive shalerite-pyrrhotite in hedenbergite skarn

No. of registrated element analyses = 1

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

Name of Locality : Nedre Gruvelia 2

(Object Id : 0238,015,01,00)

Location

County : Akershus (02) Municipality : Nannestad (0238)

Map 1:50000: Nannestad (1915-3) Map 1:250000: Hamar

Marking point: Longitude: 10.8873820 Latitude: 60.1796330

EU89-UTM Zone 32 (Coordinates IS confirmed)

X-coord: 604692 m. Y-coord: 6672913 m.

Commodity

Main Type: Base metals (Cu,Zn,Pb,Fe sulphides, As,Sb,Bi,Sn) Sub Type: Zinc

Element(s): Zn

Production

Activity: Test mining Reserves:

Prod. method: Open pit and underground mining Production:

Prod. status: Volume of dump: 60 m3

Mineralogy

Relationship Mineral Amount

Gangue mineral Pyroxene Major mineral (>10%)

Gangue mineral Feldspar Subordinate mineral (1-10%)

Gangue mineral Garnet Subordinate mineral (1-10%)

Ore mineral Sphalerite Major mineral (>10%)

Ore mineral Pyrrhotite Subordinate mineral (1-10%)

Lithology:

Relationship Rock Origin

Host rock Hedenbergite skarn Sedimentary
Original rock :Limestone

Metamorphic facies :Contact

Wall rock Biotite hornfels Sedimentary
Original rock :Argillaceous sediment

Metamorphic facies :Contact

Information(s) in free text format

Free text

Forekomsten ligger rett ovenfor (NV) for den gamle gruveveien og består av en 5 m lang dagåpning som fører inn til en vannfylt stoll med retning 230°. I dagåpningen dominerer biotitthornfels og ved stollinngangen finnes skarnomvandlet hornfels med magnetkis på stikk. På tippen nedenfor veien finnes blokker med massiv til semimassiv sinkblende og mindre mengder magnetkis og kobberkis i hedenbergittskarn.

Fieldsamples

Sample No. Sample type Miscellanrous

JS-OS2139 Dump

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

Comment :Massive/semi-massive sphalerite in hedenbergite skarn

No. of registrated element analyses = 1

JS-OS2140 Dump

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

Comment :Massive/semi-massive sphalerite and pyrrhotite+chalcopyrite veinlets in hedenbergite skarn

No. of registrated element analyses = 1

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

Name of Locality : Nedre Gruvelia 3

(Object Id : 0238,015,02,00)

Location

County : Akershus (02) Municipality : Nannestad (0238)

Map 1:50000: Nannestad (1915-3) Map 1:250000: Hamar

Marking point: Longitude: 10.8875260 Latitude: 60.1805740

EU89-UTM Zone 32 (Coordinates IS confirmed)

X-coord: 604697 m. Y-coord: 6673018 m.

Commodity

Main Type: Base metals (Cu,Zn,Pb,Fe sulphides, As,Sb,Bi,Sn) Sub Type: Zinc

Element(s): Zn

Production

Activity: Pitting Reserves:

Prod. method: Production:

Prod. status: Volume of dump: 80 m3

Mineralogy

Relationship Mineral Amount

Gangue mineral Pyroxene Major mineral (>10%)

Gangue mineral Garnet Subordinate mineral (1-10%)

Gangue mineral Feldspar Subordinate mineral (1-10%)

Ore mineral Sphalerite Major mineral (>10%)

Ore mineral Pyrite Subordinate mineral (1-10%)

Ore mineral Pyrrhotite Subordinate mineral (1-10%)

Lithology:

Relationship Rock Origin

Host rock Hedenbergite skarn Sedimentary
Original rock :Limestone

Metamorphic facies :Contact

Wall rock Biotite hornfels Sedimentary
Original rock :Argillaceous sediment

Metamorphic facies :Contact

Information(s) in free text format

Free text

Dette er en vannfylt synk med sidevegger 6 x 2 m, og kan representere en del av Nedre Gruvelia gruve som er beskrevet av Ihlen (1978). I veggene dominerer skarnomvandlet biotitthornfels. Sinkblende i granat-hedenbergittskarn finnes i blokker i den relativt store, men svært overgrodde tippen.

Fieldsamples

Sample No. Sample type Miscellanrous

JS-OS2142 Dump

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

Comment :Semi-massiv sphalerite i garnet-hedenbergite skarn

No. of registrated element analyses = 1

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

Analyse Results

from

Deposit Area 238 - 015 Nedre Gruvelia

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-OS2139 Dump 1075 137500 19 107 11 2.1 3.0

JS-OS2140 Dump 943 94900 10 82 30 1.9 1.0

JS-OS2141 Bedrock 300 77100 7 80 17 1.3 -.5

JS-OS2142 Dump 530 69800 9 98 39 4.8 -.5

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

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

JS-OS2139 -2.5 -.5 6 558.0 20 0.75 3 0 10

JS-OS2140 -2.5 -.5 3 381.0 10 1.36 2 0 4

JS-OS2141 -2.5 -.5 1 302.0 -10 9.69 4 1 1

JS-OS2142 -2.5 -.5 8 336.0 70 32.30 6 0 1

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

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

JS-OS2139 11.00 4.95 0.23 0.30 7.75 22 9 20400 14.55

JS-OS2140 12.00 5.95 0.26 0.60 8.53 21 16 17550 16.75

JS-OS2141 8.00 5.50 0.28 1.11 5.60 25 15 14850 15.45

JS-OS2142 6.00 6.22 0.25 2.16 6.67 43 14 22900 12.45

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

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

JS-OS2139 3.14 8 5.5 37.3 20.9 22 2.90 0.20 0.15

JS-OS2140 4.24 3 3.7 65.6 19.9 31 4.70 0.32 0.13

JS-OS2141 4.52 5 1.3 40.7 21.7 41 5.20 0.31 0.19

JS-OS2142 3.63 1 3.6 134.0 17.2 38 6.40 0.27 0.12

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

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

JS-OS2139 12.80 24.00 1 2 800 6500 12800 420 900

JS-OS2140 13.40 23.70 1 1 1100 5200 17600 570 600

JS-OS2141 28.70 46.80 2 2 600 8100 16400 620 100

JS-OS2142 22.30 36.70 3 3 800 7400 16600 820 700

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

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

JS-OS2139 ###### 3.90 850 1.47 0.60 0 0

JS-OS2140 ###### 4.70 1310 1.02 0.90 0 0

JS-OS2141 ###### 4.80 1300 1.56 1.10 -0 0

JS-OS2142 ###### 4.10 1110 0.65 1.10 0 0

Era:	Paleozoic	Period:	Permian
Dating:		Method:
Genesis:	Skarn formation	Form:	Lens
Main texture:	Structureless	Min. distribution:	Semi-massive (20-50 % ore minerals)

	Province:	Oslo Region
	Geotec.unit:	Akershus Graben
	Tectonic complex:
	Igneous complex:	Nordmarka-Hurdal Batholith

Relationship	Mineral	Amount
Gangue mineral	Pyroxene	Major mineral (>10%)
Gangue mineral	Feldspar	Subordinate mineral (1-10%)
Gangue mineral	Garnet	Subordinate mineral (1-10%)
Ore mineral	Sphalerite	Major mineral (>10%)
Ore mineral	Pyrite	Subordinate mineral (1-10%)
Ore mineral	Pyrrhotite	Subordinate mineral (1-10%)
Ore mineral	Chalcopyrite	Accessory mineral (<1%)

Relationship	Rock	Origin
Wall rock	Biotite hornfels	Sedimentary Original rock :Argillaceous sediment
		Metamorphic facies :Contact
Wall rock	hedenbergite skarn	Sedimentary Original rock :Limestone
		Metamorphic facies :Contact

Activity:	Pitting	Reserves:
Prod. method:		Production:
Prod. status:		Volume of dump:	80 m3

Sample No.	Sample Type	Cu*	Zn*	Pb*	Co*	Ni*	Ag*	Au#
JS-OS2139	Dump	1075	137500	19	107	11	2.1	3.0
JS-OS2140	Dump	943	94900	10	82	30	1.9	1.0
JS-OS2141	Bedrock	300	77100	7	80	17	1.3	-.5
JS-OS2142	Dump	530	69800	9	98	39	4.8	-.5

Sample No.	Pt#	Pd#	As*	Cd*	Ba*	Mo*	Sn*	Sb*	Bi*
JS-OS2139	-2.5	-.5	6	558.0	20	0.75	3	0	10
JS-OS2140	-2.5	-.5	3	381.0	10	1.36	2	0	4
JS-OS2141	-2.5	-.5	1	302.0	-10	9.69	4	1	1
JS-OS2142	-2.5	-.5	8	336.0	70	32.30	6	0	1

Sample No.	Se*	Ga*	Ge*	In*	S%	V*	Cr*	Mn*	Fe%
JS-OS2139	11.00	4.95	0.23	0.30	7.75	22	9	20400	14.55
JS-OS2140	12.00	5.95	0.26	0.60	8.53	21	16	17550	16.75
JS-OS2141	8.00	5.50	0.28	1.11	5.60	25	15	14850	15.45
JS-OS2142	6.00	6.22	0.25	2.16	6.67	43	14	22900	12.45

Sample No.	Th*	W*	Rb*	Sr*	Y*	Zr*	Nb*	Ta*	Cs*
JS-OS2139	3.14	8	5.5	37.3	20.9	22	2.90	0.20	0.15
JS-OS2140	4.24	3	3.7	65.6	19.9	31	4.70	0.32	0.13
JS-OS2141	4.52	5	1.3	40.7	21.7	41	5.20	0.31	0.19
JS-OS2142	3.63	1	3.6	134.0	17.2	38	6.40	0.27	0.12

Sample No.	La*	Ce*	Li*	Be*	Na*	Mg*	Al*	P*	K *
JS-OS2139	12.80	24.00	1	2	800	6500	12800	420	900
JS-OS2140	13.40	23.70	1	1	1100	5200	17600	570	600
JS-OS2141	28.70	46.80	2	2	600	8100	16400	620	100
JS-OS2142	22.30	36.70	3	3	800	7400	16600	820	700

Sample No.	Ca*	Sc*	Ti*	Te*	Hf*	Re*	Tl*
JS-OS2139	######	3.90	850	1.47	0.60	0	0
JS-OS2140	######	4.70	1310	1.02	0.90	0	0
JS-OS2141	######	4.80	1300	1.56	1.10	-0	0
JS-OS2142	######	4.10	1110	0.65	1.10	0	0