Resource evaluation of the Målvika tungsten deposit, Nordland
Nordic Mining contacted NGU in spring 2007 in order to re-evaluate the resource and grade of the Målvika tungsten deposit in Tosbotn municipality in Nordland, Norway. \rThe Målvika tungsten deposit is a tungsten skarn mineralisation which extends 900 m NNW-ward from the northern coastline of Tosenfj...
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ftnorgesgu:oai:openarchive.ngu.no:11250/2664767 2023-05-15T17:24:38+02:00 Resource evaluation of the Målvika tungsten deposit, Nordland Müller, Axel Furuhaug, Leif 18251 Tosbotn 2008 application/pdf https://hdl.handle.net/11250/2664767 eng eng NGU-Rapport (2008.008) (320500) Wolfram i Nordland urn:issn:0800-3416 https://hdl.handle.net/11250/2664767 Navngivelse 4.0 Internasjonal http://creativecommons.org/licenses/by/4.0/deed.no CC-BY 49 s. + 1 SKARN WOLFRAM INDUSTRIMINERALER MALMGEOLOGI SCHEELITT Report 2008 ftnorgesgu 2022-07-03T15:26:18Z Nordic Mining contacted NGU in spring 2007 in order to re-evaluate the resource and grade of the Målvika tungsten deposit in Tosbotn municipality in Nordland, Norway. \rThe Målvika tungsten deposit is a tungsten skarn mineralisation which extends 900 m NNW-ward from the northern coastline of Tosenfjord towards mountain Landnubben and ends at an altitude of about 500 m a.s.l. The skarn zone comprises marbles, metasomatic calc-silicate rocks (skarn sensu strictu), skarn-altered gneisses and granites. The ore-bearing diopside and garnet-diopside skarns form individual boudins (lenses) usually smaller than 5 m in length and 2 m in width, aligned in vein-like structures commonly 2 m wide and up to two hundred metres long. Scheelite ore is accumulated in 1-20 cm large batches distributed very heterogeneously within complexly folded and boudinaged skarns. \rThe deposit has previously been the target of three exploration phases with contrasting results since its discovery in 1972 by P. Skaarup. Some results indicate that the Målvika skarn in a world-class tungsten resource having an ore tonnage of 2 509 000 t with a grade 0.7 to 0.9 wt.% WO3, while a drilling project performed in 1983 by Sulfidmalm AS indicated only traces of tungsten.\rFieldwork was carried out during two campaigns in July and October 2007. The first campaign included 393 in situ analyses of the tungsten concentration of different rock types in the mineralised zone using a portable X-ray fluorescence diffraction spectrometer. During the second campaign, 66 bulk rock trench samples were taken, transecting nine different skarn layers.\rThe results indicate that the Målvika skarn zone is a minor tungsten deposit with possible mineable ore tonnage of 750 000 t diopside and garnet-diopside skarn with an ore grade of about 0.44 wt.% WO3. The granites of the Visttindane massif sampled 0.5 to 1 km E of Målvika have a high average tungsten content of 121 ppm reflecting an extreme enrichment of tungsten in the granite magmas. Thus, these granites are the most ... Report Nordland Nordland Nordland NGU Open Archive (Geological Survey of Norway) Norway Tosbotn ENVELOPE(12.958,12.958,65.326,65.326) |
institution |
Open Polar |
collection |
NGU Open Archive (Geological Survey of Norway) |
op_collection_id |
ftnorgesgu |
language |
English |
topic |
SKARN WOLFRAM INDUSTRIMINERALER MALMGEOLOGI SCHEELITT |
spellingShingle |
SKARN WOLFRAM INDUSTRIMINERALER MALMGEOLOGI SCHEELITT Müller, Axel Furuhaug, Leif Resource evaluation of the Målvika tungsten deposit, Nordland |
topic_facet |
SKARN WOLFRAM INDUSTRIMINERALER MALMGEOLOGI SCHEELITT |
description |
Nordic Mining contacted NGU in spring 2007 in order to re-evaluate the resource and grade of the Målvika tungsten deposit in Tosbotn municipality in Nordland, Norway. \rThe Målvika tungsten deposit is a tungsten skarn mineralisation which extends 900 m NNW-ward from the northern coastline of Tosenfjord towards mountain Landnubben and ends at an altitude of about 500 m a.s.l. The skarn zone comprises marbles, metasomatic calc-silicate rocks (skarn sensu strictu), skarn-altered gneisses and granites. The ore-bearing diopside and garnet-diopside skarns form individual boudins (lenses) usually smaller than 5 m in length and 2 m in width, aligned in vein-like structures commonly 2 m wide and up to two hundred metres long. Scheelite ore is accumulated in 1-20 cm large batches distributed very heterogeneously within complexly folded and boudinaged skarns. \rThe deposit has previously been the target of three exploration phases with contrasting results since its discovery in 1972 by P. Skaarup. Some results indicate that the Målvika skarn in a world-class tungsten resource having an ore tonnage of 2 509 000 t with a grade 0.7 to 0.9 wt.% WO3, while a drilling project performed in 1983 by Sulfidmalm AS indicated only traces of tungsten.\rFieldwork was carried out during two campaigns in July and October 2007. The first campaign included 393 in situ analyses of the tungsten concentration of different rock types in the mineralised zone using a portable X-ray fluorescence diffraction spectrometer. During the second campaign, 66 bulk rock trench samples were taken, transecting nine different skarn layers.\rThe results indicate that the Målvika skarn zone is a minor tungsten deposit with possible mineable ore tonnage of 750 000 t diopside and garnet-diopside skarn with an ore grade of about 0.44 wt.% WO3. The granites of the Visttindane massif sampled 0.5 to 1 km E of Målvika have a high average tungsten content of 121 ppm reflecting an extreme enrichment of tungsten in the granite magmas. Thus, these granites are the most ... |
format |
Report |
author |
Müller, Axel Furuhaug, Leif |
author_facet |
Müller, Axel Furuhaug, Leif |
author_sort |
Müller, Axel |
title |
Resource evaluation of the Målvika tungsten deposit, Nordland |
title_short |
Resource evaluation of the Målvika tungsten deposit, Nordland |
title_full |
Resource evaluation of the Målvika tungsten deposit, Nordland |
title_fullStr |
Resource evaluation of the Målvika tungsten deposit, Nordland |
title_full_unstemmed |
Resource evaluation of the Målvika tungsten deposit, Nordland |
title_sort |
resource evaluation of the målvika tungsten deposit, nordland |
publishDate |
2008 |
url |
https://hdl.handle.net/11250/2664767 |
op_coverage |
18251 Tosbotn |
long_lat |
ENVELOPE(12.958,12.958,65.326,65.326) |
geographic |
Norway Tosbotn |
geographic_facet |
Norway Tosbotn |
genre |
Nordland Nordland Nordland |
genre_facet |
Nordland Nordland Nordland |
op_source |
49 s. + 1 |
op_relation |
NGU-Rapport (2008.008) (320500) Wolfram i Nordland urn:issn:0800-3416 https://hdl.handle.net/11250/2664767 |
op_rights |
Navngivelse 4.0 Internasjonal http://creativecommons.org/licenses/by/4.0/deed.no |
op_rightsnorm |
CC-BY |
_version_ |
1766115730265210880 |