DNR Reports 255-1/265/266: 1988-1989 Drill Core Repository Sampling Project

Report 255-1: Duluth Complex
Report 265: Soudan Mine
Report 266: Archean Greenstone

Projects Funded by the Minerals Coordinating Committee Through the Mineral Diversification Program


Abstract extracted from page iii of Report 255-1/265/266:

ABSTRACT  These 3 projects sampled and analyzed pre-existing drill core, with an emphasis on precious metals and elements which had previously been neglected.

Project 255-1 sampled a total of 512 samples from the basal contact and inner portions of the largely mafic Duluth Complex in northeast Minnesota. The widespread nature of the mineralization associated with the basal contact portion was confirmed with 3 drill holes containing combined Au + Pt + Pd values exceeding 1000ppb and 13 other holes with lesser mineralization. Drill holes from the inner portion exhibited lower values.

Project 265 sampled 251 samples from 25 development drill holes from the Soudan Mine (Algoman-type iron formation). Gold mineralization (several hundred ppb's) appears to be breccia related. Pt and Pd values of similar values are problematical. Other samples exhibited anomalous Ba and F.

Project 266 analyzed 213 samples from 12 drill holes located in the granite-greenstone terrane of north central Minnesota (Beltrami County). Gold mineralization over 1 ppm was confirmed from previous sampling, and appeared to be associated with Bi, As, Sb, Se, S, Ag, Cu, Mo and Fe203. A weakly mineralized drill hole contained a small interval of calcareous "blackschist" alteration rock. Samples were analyzed for (varied with project) Au, Pt, Pd, Bi, Sb, As, B, Ba, S, Se, Te, Ag, Cu, Ni, Mo, W, Sn, F, Ga, Sc, Y, La, Ce, Zr, Nb, Ta, Cd, Zn, Pb, Cr, Co, V, Ti02, MgO, Fe203, MnO, Si02, Al203, P205, Li, Na20, K20, Rb, Sr, CaO, Be, Cs, and Cl.


View or download report

Report 255-1/265/266: 1988-1989 Drill Core Repository Sampling Project: 255-1 Duluth Complex, 265 Soudan Mine, 266 Archean Greenstone; analysis of drill core from Duluth complex,Soudan mine, & greenstone terranes.

(366 pages, 8.5 x 11 inches, 13.84 MB)
Authors: E.H. Dahlberg, D. Peterson, and B.A. Frey

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View or download plates

255-1, Plate 1: Hoyt Lakes - Kawishiwi Area, St. Louis and Lake Counties, Northeastern Minnesota: Compilation of Bedrock Geology and Lineaments as adapted from Morey & Cooper (1976), Chandler (1986) with Drill Hole Locations of Drill Core Repository Project.
(20.93 x 33.86 inches, full size, 1.16 mb)
Author: MN DNR, Division of Minerals

255-1, Plate 2: Drill Hole Locations and Geology, Duluth Complex: Glacial Drift Geochemistry for Strategic Minerals, Lake County, Minnesota.
(39.3 x 29.1 inches, full size, 4.63 mb)
Author: MN DNR, Division of Minerals


Download GIS data

The following zip file contains data for 976 samples extracted from fifty-three drill holes described in the Minnesota Department of Natural Resources (MnDNR), Division of Land and Minerals Report 255-1/265/266, “Drill Core Repository Sampling Project”. Each folder in the zip file contains data from the report in a different format. The data is presented in its original raw data files, a Microsoft Access database, dBase IV files, and ArcGIS File Geodatabase. The data is split up in each folder or File Geodatabase by each specific project number. For more information see the summary document below.


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