Minerals & Metallurgy

Persistent link for this collectionhttps://hdl.handle.net/11299/187105

Please note: This collection contains a variety of Reports of Investigations, Technical Reports, and Technical Summary Reports on a particular subject. For all Reports of Investigations, Technical Reports, or Technical Summary Reports, please see the following collections:

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Evaluation of Indian Iron Ore for Direct-Reduction Pellets
(University of Minnesota Duluth, 1991) Goetzman, Harold E
Investigation into Production of Iron Ore Concentrates with Less Than 3 Percent Silica from Minnesota Taconites Final Report to the State of Minnesota and the American Iron and Steel Institute
(University of Minnesota Duluth, 1991) Iwasaki, Iwao
Investigation in Production of Iron Ore Concentrates with Less Than 3 Percent Silica from Minnesota Taconites – Report One – Minntac Concentrate: A Final Report
(University of Minnesota Duluth, 1991) Benner, Blair R; Bleifuss, Rodney L
Investigation in Production of Iron Ore Concentrates with Less Than 3 Percent Silica from Minnesota Taconites – Report Three – Hibtac Concentrate: A Final Report
(University of Minnesota Duluth, 1991) Benner, Blair R; Bleifuss, Rodney L
Production of Low-Silica Concentrates from Mesabi Taconite – Report 2 Column Flotation
(University of Minnesota Duluth, 1993) Benner, Blair R
Production of Low-Silica Concentrates from Mesabi Taconite
(University of Minnesota Duluth, 1993) Benner, Blair R
Production of Two Percent Silica Concentrate for Cyprus Northshore Mining Company
(University of Minnesota Duluth, 1994) Benner, Blair R
Preliminary Testing and Pilot-Scale Processing of the Kittson County Bloating Clays
(University of Minnesota Duluth, 1996) Oreskovich, Julie A; Goetzman, Harold E
Transportation Cost Evaluation of Southeastern Minnesota Carbonates
(University of Minnesota Duluth, 1997) Zanko, Lawrence M
Geology and Cr-PGE Mineralization of the Birch Lake Area, South Kawishiwi Intrusion, Duluth Complex
(University of Minnesota Duluth, 1997) Hauck, Steven A; Severson, Mark J; Ripley, Edward M; Goldberg, Steven A; Alapieti, Tuomo
Igneous Stratigraphy and Mineralization in the Basal Portion of the Partridge River Intrusion, Duluth Complex, Allen Quadrangle, Minnesota
(University of Minnesota Duluth, 1997-12) Severson, Mark J; Hauck, Steven A
Geologic mapping of the igneous rocks of the Partridge River intrusion (PRI) within the Allen Quadrangle was conducted during the 1996-1997 period by Severson and Miller (1997). In addition to the surface geology, drill holes were logged in order to gain a better understanding of the third-dimensional geology and Cu-Ni mineralization of the quadrangle. Drill hole correlations of igneous units, along with cross-sections and a discussion of Cu-Ni±PGE enriched zones, are presented in this report. Detailed logging of drill core from over 400 drill holes indicates that there are at least seven major igneous units (Units I through VII) within the basal 3,000 feet of the PRI. These units, starting with Unit I at the base, are described in Severson and Hauck (1990) and are reiterated herein for drill holes within the Allen Quadrangle. Also present within the quadrangle and described in this report are late plug-like bodies of Oxide-bearing Ultramafic Intrusions (OUI), a Keweenawan sill within the Biwabik Iron-Formation (K-Sill), and a small Keweenawan(?) intrusive within the Archean rocks near a major fault zone. Establishment of an igneous stratigraphy for the PRI provides a framework that can be used to determine the nature and location of fault offsets between drill holes. The tenor of Cu-Ni mineralization is often locally increased along some of these faults. Fault zones, with or without increased mineralization, that are discussed in this report include faults in the Wetlegs Cu-Ni deposit, faults in the Wyman Creek Cu-Ni deposit, the Siphon Fault, and the Donora Fault. Many of these fault zones are depicted on the cross-sections that accompany this report. Enrichments in Platinum Group Elements (PGE) occur at several stratabound horizons within the Allen Quadrangle (using an arbitrary cutoff of >90 ppb Pd). All of these PGE-enriched horizons are present in sulfide-bearing troctolitic rocks that are positioned immediately below, and in some cases within, laterally continuous ultramafic layers. However, the overall Pd content in some of the horizons shows a definite decrease in an east-to-west direction. This trend suggests that as the magma of the PRI was intruded, in an east-to-west direction(?), it became progressively impoverished with respect to PGEs.
Correlating Particle Size, Geochemical, and Gamma-Ray Log Data Relationships at the Ochs Brick and Tile Company Springfield Clay Mine, Springfield, Minnesota
(University of Minnesota Duluth, 1998) Zanko, Lawrence M; Setterholm, Dale R
Borehole geophysical techniques can be very useful for characterizing the physical and chemical characteristics of sedimentary deposits. A comparison of down-hole gamma-ray response to particle size and geochemistry shows that the down-hole gamma-ray logging technique effectively distinguished between intervals of varying composition at the Ochs Brick and Tile Company (OBT) Springfield clay mine in Brown County, Minnesota. Particle size (grain size) has a first order effect on the gamma activity; it is likely that mineralogy also is a significant contributor to variations of radioactivity. The naturally occurring radionuclides K, U, and Th in selected drill core samples show that K dominates the total gamma measurements obtained from borehole logging equipment. Consistency of the U and Th activities indicate no significant post-depositional migration of isotopes with the decay series for each nuclide and reflect the average crustal abundance for each. While the collection and laboratory testing of drill hole samples should be attempted whenever possible (especially during property exploration and development), the down-hole gamma-ray probe can provide additional valuable stratigraphic information. Therefore, gamma-ray logs would be especially beneficial where: 1) extensive drill hole sampling is impractical; or 2) the drilling method makes determining stratigraphic position and unit composition difficult or impossible, e.g., auger drilling. However, if gamma-ray logging is to be used extensively during exploration or property development, down-hole sampling should still be done to establish basic relationships between the "typical" gamma-ray profile and the type of material present at the property in question.
Characterization of the Kaolin Occurrences in Northern and Central Minnesota
(University of Minnesota Duluth, 1998) Heine, John J; Patelke, Richard L; Oreskovich, Julie A
Kaolin 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.
Metallurgical Testing of Copper-Nickel Bearing Material from the Duluth Gabbro
(University of Minnesota Duluth, 1998-12) Benner, Blair R; Engesser, John; Niles, Harlan B
Comparison of One and Two Stage High Pressure Rolls Grinding followed by Ball Milling with Conventional Rod and Ball Milling
(University of Minnesota Duluth, 1999) Benner, Blair R
With the development of the autogenous wear surface, the high pressure roller press (HPR) is receiving interest from the mineral industry. Previous work by the Coleraine Laboratory had indicated energy saving using a single stage of HPR compared to rod milling and an energy saving using 2 stage HPR compared to single stage HPR. The purpose of this study was to compare three flowsheets using the same feed and producing a final size of about 85 percent passing 270 mesh. The flowsheets were as follows: (1) Rod mill followed by wet magnetic separation with ball mill grinding of the magnetic concentrate; (2) HPR closed with a 3 mesh screen followed by wet magnetic separation of the screen undersize and ball milling of the magnetic concentrate; (3) HPR closed with a 3 mesh screen with the screen undersize being upgraded by dry magnetic separation followed by open circuit HPR on the magnetic concentrate with wet magnetic separation of the HPR product and ball milling of the wet magnetic concentrate. The test work indicated that the single stage HPR required 27.25 kWh/It of new feed compared to 34.0 kWh/It for the rod mill to produce an 85 percent passing 270 mesh ball mill discharge. The two stage HPR flowsheet was even more energy efficient, requiring only 23.29 kWh/It of new feed. With the single stage HPR, the energy savings appears to be only in the coarse grinding. The ball mill grindability, as measured by the operating work index, was essentially the same for the rod mill and HPR magnetic concentrates. The two stage HPR resulted in energy savings in both the coarse grinding and in the ball milling. The operating work index for the ball mill portion only was 23.5 kWh/It of ball mill feed for the two stage flowsheet compared to about 29 kWh/It for the other two flow sheets. Davis tube tests on the ball mill discharges suggest that there is a liberation benefit associated with the two stage HPR flowsheet, but not with the single stage HPR flowsheet.
Extraction of Copper from Chalcopyrite Concentrates without Sulfuric Acid Generation via Chlorination - II. Selective Oxidation of Chlorinated Products
(University of Minnesota Duluth, 1999) Iwasaki, Iwao; Tamagawa, T.; Fu, N. X; Kobayashi, M
A low temperature chlorination-selective oxidation, followed by aqueous chloride leaching and SX-EW for producing electrolytic copper, elemental sulfur and ferric oxide was investigated for hydrometallurgical processing of a chalcopyrite concentrate. In this article, the selective oxidation phase of the process is described. The selective oxidation requires a temperature well above the CuCl-FeCl3 eutectic points. The test procedure was developed with a batch reactor and then tested with a continuous reactor. The process was initiated by adding small amounts of chlorinated samples to a fluidizing bed of dead-roasted sulfide concentrate micro-pellets. The selectively oxidized samples thus prepared were shown to fully dissolve copper, while virtually all the iron remained undissolved.
Characterization of Residue from the Pressure Oxidation Leaching of Bulk Copper-Nickel Sulfides from the Duluth Gabbro
(University of Minnesota Duluth, 1999) Benner, Blair R; Niles, Harlan B
The copper-nickel bearing material in the Duluth Gabbro represent a potentially significant reserve of copper and nickel with lesser amounts of cobalt and platinum group elements (PGEs). To help promote the development of this resource, the Coleraine Minerals Research Laboratory (CMRL) has conducted a series of investigations into methods of processing the material. A bulk sulfide flotation process followed by oxidation pressure leaching resulted in high extractions (>98 %) of the copper and nickel in the flotation concentrate. During the leaching, the iron in the flotation concentrate leaches and precipitates as either hematite (crystalline or amorphous) or as a basic iron sulfate (jarosite). The leaching should also leave the PGEs in the residue. If the hematite was present as a crystalline material, then if may be possible to recover a high grade iron product from the residue. If any PGE minerals could be found, then it may be possible to develop a method to recover and concentrate the PGEs. The Minnesota DNA through the Minerals Coordinating Committee funded the current study. The purpose of the research was to characterize the leach residue as to the iron bearing material and to determine if any PGE minerals could be found either by X-ray diffraction (XRD) or by electron microprobe analysis.
Extraction Metallurgy of Copper from Chalcopyrite Concentrates without Sulfuric Acid Generation via Chlorination - III. Integration of Gaseous Chlorination and Selective Oxidation
(University of Minnesota Duluth, 1999) Iwasaki, Iwao; Tamagawa, T.; Fu, N. X; Kobayashi, M
A 3-stage fluidizing bed process of chlorination, selective oxidation and sulfur chloride conversion was tested for processing of a chalcopyrite concentrate. It was found that the use of excess oxygen was essential to a stable operation in the oxidation reactor. The oxygen-excess gas will inevitably cause the oxidation of the sulfide concentrate in the chlorination and sulfur chloride conversion reactors. A new flowsheet is proposed to separate the chlorination and the selective oxidation steps with separate flow paths of the fluidizing gases, thereby preventing the passage of oxygen-excess gas in the chlorination and sulfur chloride conversion reactors. The feasibility of the proposed flowsheet was demonstrated in a laboratory-scale fluidizing bed setup.
Extraction of Copper from Chalcopyrite Concentrates without Sulfuric Acid Generation via Chlorination - I. Gaseous Chlorination of Sulfide Concentrates
(University of Minnesota Duluth, 2000) Iwasaki, Iwao; Tamagawa, T.; Tabaian, S. H; Fu, N. X; Kobayashi, M
A gaseous chlorination process for hydrometallurgical treatment of a chalcopyrite concentrate was investigated. The overall process is visualized to consist of low temperature chlorination-selective oxidation, followed · by aqueous chloride leaching and SX-EW for producing electrolytic copper, elemental sulfur and ferric oxide. In this article, the chlorination phase of the process is described. Initially, the chlorination behavior of chalcopyrite-concentrate micro-pellets was investigated using a small batch-type fluidized bed reactor. The optimum conditions thereby established were used in continuous chlorination tests. The chlorinated products thus prepared were used in the selective oxidation phase of the investigation.
Mercury Removal from Induration Off Gas by Wet Scrubbers
(University of Minnesota Duluth, 2000-11-15) Benner, Blair R
During the induration of taconite pellets, green balls are heated to greater than 2200°F. A previous study indicated that greater than 90 percent of the mercury contained in the green balls is volatilized during induration. Some of the volatilized mercury is removed by the gas scrubbers. Studies on coal burning power plants indicate that the mercury in flue gas is present as either elemental mercury or as divalent mercury. In power plant scrubbers, the majority of the divalent mercury is removed, but very little elemental mercury is removed by the scrubbers. The particulate matter in the off gas appears to remove a significant portion of the mercury that is removed. It is thought that the off gas chemistry and the scrubber water chemistry could affect the removal of mercury. To determine if the scrubber water chemistry could affect the removal of mercury from taconite pelletizing off gases, the Minnesota Department of Natural Resources' (MNDNR) environmental cooperative funded a study to sample around the scrubbers from the plants equipped with wet scrubbers to determine if water chemistry affects mercury removal. Another objective of the study was to determine the role of solids entrained in the off gases and removed by the scrubbers. These solids are returned to the process. If they were discarded, then some amount of mercury could be eliminated from the system, but at a cost of iron units. Samples were obtained from Minntac, EVT AC, Minorca, Hibtac and Northshore. With the exception of the mercury analyses, all chemical analyses were conducted at Coleraine. Mercury analyses were run by Frontier Geosciences of Seattle, Washington. While the various plants have different scrubber configurations and scrubber water chemistries, these differences appeared to have no significant affect on mercury removal. Accurate mercury balances were not possible because mercury content in the fired pellets from all of the plants was below the detection limit of about 0.6 parts per billion (ppb). Solids entrained in the off gases removed significantly more mercury than the scrubber water. Of the mercury removed in the scrubber systems, the amount contained in the solids ranged from 75 percent at Northshore to greater than 99 percent at EVTAC. The minus 10 micron fraction of the solids in the off gases appears to remove the most mercury. Analysis of the solids that are continually recycled to the Minorca wet scrubbers indicates a high capacity for mercury removal (the solids assayed over 3000 ppb mercury). This result indicates that the mercury should remain with the solids and should not leach if the solids were sent to the tailings basin.

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