DNR Open-File Project 373: 2008-2010; St. Louis County Vermilion Greenstone Drill Core Assays

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1. About the Project:

The Project 373 area comprises several townships in northern St. Louis County, Minnesota (see location maps in Fig. 1). The Archean rocks are part of the Wawa Subprovince of the Superior Province of the Canadian Shield. Rocks consist of Semi-quantitative2 volcanic-sedimentary sequences and intrusions. Most rocks have been subjected to greenschist facies metamorphism. Outcrop exposure is variable, but good compared with most of Minnesota. Past sampling, maps, and reports have been produced by the Minnesota DNR, the Natural Resource Research Institute, and the Minnesota Geological Surveys.

A “gold rush” in 1865 lead to the discovery of iron ore, but little gold was found. About 100 million tons of direct shipping magnetite and hematite ore within Algoma type Banded Iron Formation(s) (BIF) came from this greenstone. The village of Soudan hosted the first iron mine in Minnesota, with the city of Ely hosting another five major mines. Numerous smaller mines also existed. The iron formation is responsible for one of the strongest magnetic anomalies in Minnesota (Fig. 2). Vermilion underground iron production ceased in Ely in 1965, but several episodes of gold and base metal exploration followed. Exploration activities found numerous gold and base metal showings.

The Project 373 work is meant to complement existing data. 

2. Monthly Data Releases for Project 373:

July 2010: The following open-file datasets were released:

read_of0710_p373 - Word file with data release organization and limitations This link leads to an Word document. (27 kb)

p373_openfile_0710_sample_info.xls - Excel file sample descriptive and location informationThis link leads to an Exel document. (42 kb)

p373_openfile_0710_chemistry.xls - Excel file with ALS Chemex laboratory results This link leads to an
Exel document. (614 kb)

p373_openfile_0710_chem_standards.xls - Excel file with DNR submitted standards and accepted values This link leads to an
Exel document. (98 kb)

p373_coa_29190_11677484.pdf - PDF file of received chemistry resultsThis is a
PDF file. You will need Adobe Acrobat Reader to download it. (184 kb)

p373_qcdoc_29190_11677490.pdf - PDF file of ALS Chemex quality control dataThis is a
PDF file. You will need Adobe Acrobat Reader to download it. (303 kb)

p373_ddh_list.xls - Excel file with information about drill hole locations (contact project leader with questions) This link leads to an
Exel document. (29 kb)

RE10060081.csv - CSV file of received chemistry data This link leads to an
Exel document. (86 kb)

RE10060081QC.csv - CSV file of received chemistry quality control data This link leads to an
Exel document. (31 kb)

These analyzed samples came from 12 drill holes in greenstone belt rocks that were historically drilled for gold, base-metals, and iron formation. Drill hole samples, and related exploration data, are currently stored at the Minnesota Drill Core Library in Hibbing, Minnesota. The drill holes are located within a large, accessible Archean greenstone terrane within the State of Minnesota between Tower and Ely, Minnesota.  Sampling was partially guided by the use of the MnDNR’s hand-held X-Ray Fluorescence (XRF) analyzer instrument. This new work consists of laboratory analysis of 212 samples by ALS Chemex.

January 2009: The following open-file report was released:

Drill Core Evaluation of Vermilion Greenstone Belt, Gold Mineralization, Northeast MinnesotaThis is a PDF file. You will need Adobe Acrobat Reader to download it.
(61 pages, 8.5 x 11 inches, 6.8 MB)

November 2008: The following presentation report was released:

Project 373, Vermilion Greenstone Gold, New Results from Drill HolesThis is a PDF file. You will need Adobe Acrobat Reader to download it.
(60 pages, 8.5 x 11 inches, 8.6 MB)

For more information:

Barry Frey
1525 Third Ave East 
Hibbing, Minnesota 55746
tel. (218) 231-8450
barry.frey@state.mn.us

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