Browsing by Author "Patelke, Richard L"
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Item The Babbitt Copper-Nickel Deposit: Part A: Digital Drill Hole Data Files for the Babbitt and Serpentine Copper-Nickel Deposits(University of Minnesota Duluth, 1994-09) Patelke, Richard LThe main objective of this investigation is to assist Arimetco International, Inc. in their evaluation of establishing a non-ferrous mine in northeastern Minnesota. This portion of the report presents data compilation work done on the Babbitt and Serpentine Cu-Ni deposits by the NRRI. The purpose was to put all available copper-nickel-sulfur assays, precious metal assays, RQD (Rock Quality Designation) information, and down hole drill hole survey data into a uniform digital format.Item The Babbitt Copper-Nickel Deposit: Part B: Structural Datums(University of Minnesota Duluth, 1994-09) Severson, Mark J; Patelke, Richard L; Hauck, Steven A; Zanko, Lawrence MThis portion of the investigation concentrated on determining specific structural and stratigraphic datums within the Babbitt Cu-Ni deposit of the Partridge River Intrusion, Duluth Complex, northeastern Minnesota. Structural datums and footwall lithologies were obtained by relogging the footwall portions of all surface drill holes (391) within the confines of the deposit. Specific lithologies recorded during relogging included depth to: 1) basal contact of the Duluth Complex with the footwall rocks; 2) distinctive units within the footwall Virginia Formation; and 3) top of the underlying Biwabik Iron-formation and the specific iron-formation submembers intersected in drill hole. In addition, 100 surface drill holes were relogged in detail and compared with 166 previously relogged drill holes. The top of Unit I, the main sulfide-bearing igneous unit of the Babbitt deposit, was determined for all 266 drill holes that were relogged. The top of the first significant sulfide-bearing zone (not always the top of Unit I) was also determined for the relogged drill holes. All these datum points are used to generate several contoured surface maps to gain a better understanding of the main structural features present within the Babbitt deposit. The contoured surface for the top of the Biwabik Iron-formation is an excellent means of displaying the major structural features, i.e., the Local Boy Anticline, Bathtub Syncline, and Grano Fault. These same features are evident in the contoured surface of the basal contact and indicate that pre-existing structures in the footwall were important to how the basal portion of the Duluth Complex was emplaced. Datum points within the upper portion of the Duluth Complex also suggest that these structures were reactivated throughout the emplacement history of the Duluth Complex (see discussion in Part C). Some of the structures were also important controls of Cu-Ni mineralization. A contoured surface of the bedrock ledge is also presented for the Babbitt deposit. Several structural features are outlined by the bedrock ledge. A crude subsurface geologic map is also portrayed for the bedrock ledge. In addition, an isopach map of glacial overburden thickness is included in this report.Item The Babbitt Copper-Nickel Deposit: Part C: Igneous Geology, Footwall Lithologies, and Cross-Sections(University of Minnesota Duluth, 1996-03) Severson, Mark J; Patelke, Richard L; Hauck, Steven A; Zanko, Lawrence MTwenty-five cross-sections are presented that display the detailed igneous geology for several areas of the Babbitt Cu-Ni deposit. Shown in the cross-sections are the stratigraphic relationships of at least seven major igneous units - Units I through VII of the Partridge River Troctolite Series (PRTS). However, not all seven units are equally present throughout the deposit due to "pinch-out" relationships and lateral gradational rock type changes. In addition to these seven units, three new units are briefly discussed and include the: 1) Bathtub Layered Series (BTLS) of Hauck (1993); 2) Basal Ultramafic Unit (BU Unit) of Severson (1994); and 3) Upper Layered Series (ULS). Small plug-like bodies of Oxide-bearing Ultramafic Intrusions (OUIs) are also locally present within the Babbitt deposit. They intrude the rocks of the PRTS and are often positioned adjacent to, or within, fault zones. Rock types found within the footwall rocks beneath the Complex at the Babbitt deposit are also described. Metamorphic textural variations are described for select units within the Virginia Formation (RXTAL, DISRUPTED, and BDD PO units). These textural variations indicate that the effects of structural deformation, recrystallization, and partial melting are more pronounced than previously thought. The exact origin of the textures is unknown, but is believed to be associated with early stages of Duluth Complex emplacement. Also present within the basal portion of the Virginia Formation are early intrusive rocks that predate emplacement of the Partridge River intrusion (PRI). These early intrusive rocks are referred to as the Virg Sill and "Massive Gray" Unit ("MG" Unit); both are interrelated and are submembers of a single composite sill. At least three major structural features are present in the footwall rocks and include the: Local Boy Anticline, Bathtub Syncline, and Grano Fault (for a more detailed discussion see Part B - Severson et al., 1994). During intrusion of the Partridge River intrusion, specifically during emplacement of the lowest unit (Unit I), the Local Boy Anticline and Bathtub Syncline were important factors controlling how the base of the Complex was formed (see Part B). In addition, these same structures also appear to have been repeatedly reactivated during continued emplacement of the Complex and affected the distribution of specific units within overlying Unit III and the BTLS. Also, the distribution of the "MG" and Virg Sill units are affected by these same two structures. These relationships suggest that reactivation of the structures created "void spaces" into which specific PRTS units were emplaced. The exact details and of this complicated emplacement history have yet to be unraveled.Item Bedrock Geology and Lode Gold Prospect Data Map of the Mud Creek Road Area, Northern St. Louis County, Minnesota(University of Minnesota Duluth, 2004) Peterson, Dean M; Patelke, Richard LGold mineralization in northeastern Minnesota occurs in numerous prospects east of Lake Vermilion in rocks of the Bass Lake sequence (Peterson and Jirsa, 1999) of the Neoarchean Wawa Subprovince of the Canadian Shield. This zone of abundant gold mineralization is bounded to the south by the Mud Creek shear zone and to the north by the Vermilion fault (Fig. 1). The main access to these prospects is along the Mud Creek road (County Road 38). A brief period of mineral exploration for lode-gold deposits in this immediate area of the Vermilion district occurred in the mid 1980s to early 1990s. These programs typically consisted of grid-based geologic mapping, bedrock sampling, ground geophysics, and the completion of soil geochemical surveys. Personal conversations with many of the people involved in gold exploration programs in the area, and compilation of all exploration data from the district as a whole by Peterson (2001), has led to the conclusion that interpretation of linear structural elements exposed in outcrops were typically not used in designing exploratory drilling plans in the map area. Therefore, many of the prospects discovered on the surface as a result of these exploration programs remain untested by drilling. The goal of this project was to try to determine the downdip orientation of specific gold mineralized zones discovered in these previous exploration programs, and therefore, encourage new gold exploration in the area. Brief descriptions of the techniques used in the project are described below. Detailed geologic outcrop maps (at scales ranging from 1:1,000 to 1:3,000) were completed for a number of the gold prospects located in the field area. The mapping was focused on structural (shear zones, lineations, intersecting foliations and small-scale folds), geological (contact relationships, competence contrasts), geochemical (gold assays, trace element characteristics), and alteration (Fe-bearing carbonate, sericite, pyrite, silicification) features within and around areas of gold mineralized exposures.Item Bedrock Geology Map and Cu-Ni Mineralization Data for the Basal Contact of the Duluth Complex West of Birch Lake, St. Louis and Lake Countiues, Northeastern Minnesota(University of Minnesota Duluth, 2004) Peterson, Dean M; Patelke, Richard L; Severson, Mark JThis map is the outcome of eight days of field mapping by Dean M. Peterson in 2001 (Peterson, 2002e), and 6 days of mapping by the authors in 2002. The discovery of large (hundreds of meters long) gossanous expanses of Cu-Ni mineralized rock in the basal zone of the South Kawishiwi intrusion (SKI) in 2001 (in a historically under-mapped area) lead to the acquisition of funds to complete the subsequent detailed geological mapping that resulted in the publication of this map sheet. The mapping was completed at a scale of 1:3,000 and was concentrated within the Cu-Ni-PGE mineralized horizon immediately east of the basal contact of the Duluth Complex. Three mapping traverses were completed to the west into the footwall Neoarchean Giants Range batholith, and to the east into the unmineralized rocks of the SKI stratigraphically overlying the mineralized zone. The information generated from the detailed geological mapping was integrated with previous work by Phinney (1967), Miller et al. (2001), and Miller et al. (2002c), outside of the corridors of detailed mapping during the final compilation of this geologic map (see Fig. 1). In addition, geologic units intersected in the scattered drill holes in the area (see Severson, 1994) have been projected updip to the surface. The faults depicted on the map are interpreted from analysis of aeromagnetic data, steepening of the dip of the basal contact of the Duluth Complex (Figs. 2 and 3), and topographic lineaments. Digital data will be available online at http://www.nrri.umn.edu/egg/ in the fall of 2004.Item Characterization of the Kaolin Occurrences in Northern and Central Minnesota(University of Minnesota Duluth, 1998) Heine, John J; Patelke, Richard L; Oreskovich, Julie AKaolin mining and exploration in Minnesota has been concentrated in the Minnesota River Valley, in the south-central part of the state. Potential exists for kaolins in northern and central Minnesota. Using the resources of the Minnesota Department of Natural Resources Drill Core Repository, over 1,250 drill logs were reviewed for references to kaolin bearing materials. This process resulted in 170 drill holes that contained references to kaolin bearing materials. Examination of these drill holes resulted in the selection of 60 drill holes containing kaolinitic materials for detailed logging. Detailed logging resulted in the collection of 287 samples from 40 drill holes. All samples were run for particle size analysis, and 27 selected samples were run for geochemistry. Many regions in the study area show potential for kaolin clay exploration. All areas sampled have favorable geochemistry and particle size analyses for current industrial clay uses, which include brick manufacturing, ceramics, and portland cement production. The areas with the greatest potential are Cass, Crow Wing, Stearns, Chippewa, Lac Qui Parle, and Pope Counties. Other possible uses for these clays include, refractory materials, fillers and pigments for industrial and agricultural applications, and coating and fillers for the paper industry. Exploration for kaolin deposits may be hindered by the lack of outcrop and thick overburden in some of these areas. The use of geophysical techniques, coupled with the examination of other drill holes and water well log data, may aid in the location of areas of further interest for exploration companies.Item Exploration Drill Hole Lithology, Geologic Unit, Copper-Nickel Assay, and Location Database for the Keweenawan Duluth Complex, Northeastern Minnesota(University of Minnesota Duluth, 2003) Patelke, Richard LThis report and database compiles virtually all publically available drill hole location data, lithological logging data, copper-nickel assay data, and rock quality data for about 2,145 exploration drill holes in and near the Keweenawan Duluth Complex in northeastern Minnesota. This database covers about 1,779,600 feet of drilling over about 70,000 lithological, and about 70,000 separate assay intervals. All of this drilling is in St. Louis, Lake, and Cook counties. The digital data are presented in an industry standard (Gemcom for Windows) exploration and mine modeling software format, as well as spreadsheet and comma-delimited files for use in other programs. This format can be adapted for use in a GIS program such as ArcView. The purpose of this report is to make these data available to mineral exploration companies in a format almost immediately usable by them.Item A History of Copper-Nickel and Titanium Oxide Test Pits, Bulk Samples, and Related Metallurgical Testing in the Keweenawan Duluth Complex, Northeastern Minnesota(University of Minnesota Duluth, 2005) Patelke, Richard L; Severson, Mark JThis project describes the bulk samples (test pit and some drill hole composites) taken from various locations in the Duluth Complex since the 1960s, with minor background information on earlier work. Included are: 1) descriptions of sample areas; 2) local geology and expected grade of samples; 3) rationale for sample location; 4) review of the metallurgical results; and 5) an index of where the complete data (mostly metallurgical) can be found. Historical (Native American and early settlers) native copper, native silver, accidental iron ore prospects, and any other test pits are not covered in this report. The copper-nickel and iron-titanium-oxide deposits associated with rocks of the Duluth Complex have had a number of large bulk samples removed for metallurgical testing since the 1960s. There are at least six bulk sample sites in the South Kawishiwi intrusion (SKI) and about fourteen bulk sample sites in the Partridge River intrusion (PRI; Table 1.) Common to most of these bulk samples have been erratic grades, relative to what had been outlined by prior drilling, and difficulty in defining and producing an “average” or “typical” mineralized sample. Our research experience has led us to believe that the mineralization is borderline chaotic over short distances within the mineralized zones of these deposits. Thus, in many instances, it may not be possible to obtain an “average” mineralized bulk sample with samples of small size (depending on how one defines “average”). It is important to note that once a bulk sample site was chosen by a mining company, based on limited on-site drilling, no detailed drilling or mapping was conducted prior to collecting the sample.Item National Underground Science and Engineering Laboratory (NUSEL): Geological Site Investigation for the Soudan Mine, Northeastern Minnesota(University of Minnesota Duluth, 2003) Peterson, Dean M; Patelke, Richard LItem Technical Reference for Minnesota's Industrial Mineral Wastes/By-Products(University of Minnesota Duluth, 2004-09) Oreskovich, Julie A; Zanko, Lawrence M; Patelke, Richard L; Heine, John J