Lehmann Family Fund Collection of
Mineral Exploration Documents
(including the Polaris Joint Venture)

Image of historic mineral exploration map

Scroll down for information on the August 2016 data release


A generous gift from the Lehmann Family Fund has made historical mineral exploration data available and accessible to the public and to the industry. The donation honors the lifelong work of Ernie Lehmann, an internationally-renowned mineral explorer who was a pioneer in evaluating the mineral resource potential of Minnesota’s greenstone belts and Duluth Complex.

The Polaris Joint Venture (PJV) was a large-scale five year-long exploration campaign that targeted high-grade Copper-Zinc prospects in the greenstone belts of Northern Minnesota during the early 1980's. Ernest K. Lehmann & Associates (ELA), in partnership with Getty and Billiton, completed airborne and ground geophysical surveys, geologic mapping, geochemical sampling, and 50 drill holes within a 13,000 square mile study area that stretched roughly from Bemidji to Ely. This new data will accompany the drill core samples already deposited at the DNR's drill core library located in Hibbing, Minnesota.

Largely funded by private industry, historical mineral exploration records are the primary source of information about the buried, undiscovered, and undeveloped mineral deposits in the state. The records represent a significant investment of time, capital and human effort to discover and map the state's minerals.

In addition to mineral exploration, the use of the geoscience information contained in the records by state agency geologists will inform state land administration and groundwater planning decisions as well as university researchers to further discover the geologic history of the state.

First time visiting

Here are scanned documents from the collection and a new DNR summary map that will provide context to the collection for first time visitors.
Overview map from 1982 (.pdf)
Project overview from 1986 (.pdf)
Chronology of project activities from 1986 (.pdf)
Exploration footprints map (DNR, 2017) (.pdf)

Scanned documents, data, & web map

Data updated in March 2017

Here are ways to access the online compressed documents. Scans of better resolution available on request. 
Click each topic below to expand.
Click again to hide.

Search using Microsoft Excel

Download these Microsoft Excel tables to view additional information about each document and links to individual PDFs.
Lehmann Family Fund Collection of Mineral Exploration Documents (includes the Polaris Joint Venture) (.xlsx, as of March 2017)

Search using GIS

The DNR has created GIS data that portrays the spatial footprints for the Lehmann Family Fund Collection of mineral exploration documents (including the Polaris Joint Venture). The GIS data includes URL links to view or download the document(s) for a spatial footprint area.

GIS data displays the footprints of mineral exploration footprints of the Lehmann Family Fund Collection, which includes the Polaris Joint Venture (as of March 2017).

Web map search

The GIS spatial footprints can be viewed online, with no GIS software necessary. The data can be found on the Drill Core Library and Mineral Exploration Collection web map app under the left-hand bar titled 'DNR Mineral Exploration Collection 2 - Lehmann Family Fund Mineral Exploration Documents'. Within the web map you can click on a mineral exploration footprints to view (and download) the associated documents. The web map also features Minarchive's exploration footprints, background geologic data, and DNR state mineral leasing data for reference.

Drill Core Library & Mineral Exploration Collection Web Map App

Contact us

If you find the quality of an available scan lacking, please contact us and we will send you a larger, less compressed file. If you have other questions, concerns, or problems downloading the content please contact us:

DNR Lands and Minerals Division
1525 Third Avenue
Hibbing, MN 55746
Matt Carter, [email protected]

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August 2016 data release

The Lands and Minerals Division's goal for this collection is to protect and preserve the original documents while making them readily accessible to the public via the internet. There are now approximately 20,000 individual pages available from this collection comprised of 2,056 documents. The documents include reports, maps, and raw data; nearly all have been scanned and are available online. Certain documents are only available to view at the Hibbing Lands and Minerals office due to logistical constraints of scanning very large and fragile documents or documents in unusual formats. The Lehmann Family Fund donated $10,000 to preserve and catalog these documents.

Users may search through the online documents by choosing from three tools that are available in the column on the right. There is a map that allows you to select a geographic location and find the associated documents; or use an excel spreadsheet to search through the documents; or use Geographic Information System to search the records.

In this latest data release, you will find:

  • Additional data collected by the Polaris Joint Venture (PJV) program.
  • Datasets gathered by the North Central Mineral Ventures company, spanning from the late 1960s to the mid-1970s. Many of North Central Mineral Venture’s exploration findings had an impact on the initial directions of PJV.
  • Data collected for the Galebrook Project. This was a joint venture between Lehmann Exploration Management and U.S. Borax Chemical Corporation in the late 1980s. This venture was based findings from the Gale Brook area selected by the PJV.
  • Information and datasets from Ernie Lehmann’s diamond prospecting programs in Minnesota in the mid-1980s through early 1990s. The findings of the PJV informed the starting locations of diamond prospecting projects.

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