Browsing by Subject "Leaching"
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Item An Addendum to: Geology and Sulfide Content of Archean Rocks Along Two Proposed Highway 169 Relocations to the North of Sixmile Lake, St. Louis County, Northeastern Minnesota and Geologic Investigations in the Armstrong Lake Area(University of Minnesota Duluth, 2012) Severson, Mark J; Heine, John JThis report summarizes the geochemical results pertaining to the sulfur contents of rock samples collected in the Sixmile Lake area, and thusly, serves as an addendum to a previous report by Severson and Heine (2010). Geologic mapping in the Sixmile Lake area was initiated at the request of the Minnesota Department of Transportation (Mn/DOT) and concentrated on areas where Highway 169 could potentially be re-routed. The second purpose of this addendum is to provide the appropriate GIS-related shape files that were omitted from the initial report by Severson and Heine (2010). These shape files have been finalized and are provided in this report. In addition, reconnaissance geologic mapping took place along other Highway 169 relocations in the Armstrong Lake/McComber Mine area. The results of that endeavor are provided in this report. The results of sulfur analyses for samples collected from the Sixmile Lake area show that most of the samples with ≥ 0.15% analyzed sulfur contents were correctly mapped as “anomalous sulfide zones” by Severson and Heine (2010). However, there were several instances where the visually-estimated pyrite contents did not compare well with the actual sulfur contents due to a “nugget effect” variation in the third dimension. This “nugget effect” variability is troublesome and suggests that some form of drilling should take place in the areas of future road cuts in order to obtain more representative S% values. Examination of rock exposures and recent drilling of the iron-formation in the vicinity of Shaft #2 in the McComber Mine area indicates that pyrite is present in much higher amounts when compared to Sixmile Lake. Thus, additional drilling will be needed in the McComber Mine/Shaft #2 subarea, and possibly in the Clear Lake subarea, in order to obtain a better understanding of the amount of pyrite present.Item Duluth Complex Mineral Separations(University of Minnesota Duluth, 2001) Niles, Harlan BThe Minerals Division of the Minnesota Department of Natural Resources (DNR) is examining leaching characteristics of minerals that would likely be present in tailing produced by mining and concentrating copper- and nickel sulfide-bearing ores from the Duluth Complex. The Coleraine Minerals Research Laboratory (CMRL) of the Natural Resources Research Institute submitted a project proposal to provide concentrates of silicate minerals for DNR leaching studies. The DNR accepted the proposal and funded the project for $14,210.Item 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, MA 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.Item 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, MA 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.Item Geology and Sulfide Content of Archean Rocks Along Two Proposed Highway 169 Relocations to the North Of Sixmile Lake, St. Louis County, Northeastern Minnesota(University of Minnesota Duluth, 2010) Severson, Mark J; Heine, John JItem Influences of management and the environment on phosphorus leaching in corn-soybean systems in Minnesota(2018-08) Leverich, LeannaPhosphorus is an essential nutrient in corn and soybean systems for maximizing yields and profits in Minnesota. The over-application of P fertilizer can lead to the impairment of freshwater ecosystems throughout the Midwest and United States. Excess P in freshwater can ultimately lead to eutrophication and detrimental species population shifts. To help mitigate such pollution here in Minnesota, research was completed to identify the risk of P loss to the environment through leaching. The objectives of this research were to 1) Evaluate the potential for water soluble P loss from top soils (0-15 cm) across a range of initial soil test phosphorus (STP) levels and timings of leaching events after fertilizer application (denoted as “leachtimes”); 2) Determine the effect of soil type, soil properties, initial STP level, various leaching intensities, and P fertilizer source on P leaching losses; 3) Assess the predictability of P loss through leaching using routine soil tests, leaching intensity, soil properties and sorption estimates. Six sites throughout the state of Minnesota under long-term P management were used for this study. Intact soil columns were taken from all sites to identify the risk of P leaching from various Minnesota soils with varying chemical and physical properties. Columns were leached at 10x field capacity to balance for various water holding capacities among sites. The influences of soil test P (STP), soil type, and timing of a leaching event after fertilization were evaluated for effects of P leaching as P leachate concentration, P load, and percent of P fertilizer leached. In addition, a second set of intact columns were collected from three of the six sites for further evaluation of leaching intensity and P fertilizer source on P leaching potential. Leaching intensity was applied at three rates 200, 400, 600 mL to evaluate effects on P leaching. Liquid P fertilizer, dry P fertilizer, manure, and liquid P fertilizer with the addition of AVAIL® were evaluated for influences on P leaching. Results from this study indicated P leaching is a substantial loss pathway with greater losses occurring at higher STP levels. Leachtime also significantly affected P leaching losses, with immediate leach events after fertilizer applications leading to losses up to 33 percent. Volume of the leaching event was found to be the driver of P load, as P concentrations remain consistent with volume applied, and concentrations were not diluted. Phosphorus fertilizer source also significantly impacted P leaching losses, with dry fertilizers leaching significantly more P than liquid or manure sources. Results indicated soil hydrology may be substantially influencing leaching, with preferential pathways leading to greater P leaching losses. Relating P leaching losses to soil test measures was moderately successful; however, relationships were not strong enough to lead to P leaching loss predictions. Relationships were strongest among the environmental soil tests, Water extractable P (WEP) and BioAvailable P (BAP), and the Olsen P (OP) routine soil test. Further research is necessary to fully understand P leaching especially at deeper depths.Item Low Temperature Gaseous Chlorination for Sulfur Oxide Free Extraction of Copper from Chalcopyrite Concentrates(University of Minnesota Duluth, 2002) Iwasaki, Iwao; Fu, N. X; Tabaian, S. H; Tamagawa, T.; Kobayashi, MLaboratory investigations of gaseous chlorination-selective oxidation process on primary copper sulfide concentrates are described for producing copper chlorides, elemental sulfur and ferric oxide. The copper chlorides can then be leached, purified and electrolyzed to produce metallic copper and chlorine regenerated for recycle. When a process, originally proposed on a pyrite concentrate analyzing 2.5%Cu using a two-stage reactor, was applied to a Cu, Ni sulfide concentrate analyzing 9%Cu, the process had to be modified to a three-stage reactor by adding a sulfur chloride conversion unit. In this manner, operational problems associated with the formation of Cu-Fe chloride eutectics and sulfur chlorides could be circumvented. When the process was extended to a 29%Cu chalcopyrite concentrate, the use of excess oxygen was found to be necessary to stabilize the operation of the oxidation reactor. A flowsheet was further modified to separate the chlorination and selective oxidation units with separate flow paths of fluidizing gases, thereby preventing the oxidation of sulfide feed in the chlorination reactor. Leaching of selectively-oxidized samples produced solutions analyzing Cu concentrations in excess of 100 g/L with Fe/Cu ratios of less than 0.03 and with Cu extractions of over 99%. Leach residues were readily filterable with cake moisture contents of 20 to 25%.Item Metallurgical Testing of Copper-Nickel Bearing Material from the Duluth Gabbro(University of Minnesota Duluth, 1998-12) Benner, Blair R; Engesser, John; Niles, Harlan BItem Nitrate Leaching Mitigation with Kura Clover and Rye Covers for Corn and Soybean in Irrigated Sands(2021-10) Wayment, JessicaIn addition to best nitrogen (N) management practices, integration of cover crops, such as winter rye (Secale cerale L.) and kura clover (Trifolium ambiguum), into annual row crops may be an effective mitigation strategy to reduce nitrate (NO3-- N) leaching from irrigated sandy soils. This study was conducted in the Central Sands region of Minnesota from 2016-2020. The objectives were to evaluate, at variable N rates, rye and kura’s ability to reduce NO3-- N leaching and determine the impacts of the covers on soil N availability, corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] N uptake, and grain yield in continuous corn (CC), corn-soybean (CSb) and soybean-corn (SbC) cropping systems. From 2017-2020, kura reduced NO3-- N leaching by 69% (42 kg NO3-- N ha-1) compared to no cover crop but inter-crop competition resulted in reduction of 26% (2.3 Mg ha-1) in corn and 21% (0.8 Mg ha-1) in soybean grain yield. While inter-crop competition was successfully reduced with chemical suppression of kura, this also reduced the NO3-- N leaching benefit of kura. Inconsistent establishment and growth of rye resulted in variable results across years. Overall, however, rye had little effect on corn yield and reduced NO3-- N leaching compared to no cover by 11% (7 kg NO3-- N ha-1) in CC and 26% (19 kg NO3-- N ha-1) in CSb. In SbC, rye reduced yields 5% (0.2 Mg ha-1) and increased leaching by 25% (15 kg NO3-- N ha-1). Regardless of cropping system or cover crop variables, applying N above optimum rates provides no agronomic benefit and increases risk of NO3-- N leaching. Restricting N applications below optimum rates provides little or no NO3-- N leaching benefits and reduced grain yield. While best N management practices combined with cover crops can meet the need for grain production and minimize NO3-- N leaching in certain situations, minimizing inter-crop competition, and ensuring adequate annual rye establishment and N availability will prove essential to wide adoption of these alternative management systems.Item Performance of Taconite Aggregates in Thin Lift HMA: Final Report - January 31, 2012(University of Minnesota Duluth, 2012) Zanko, Lawrence M; Johnson, Ed; Marasteanu, Mihai; Patelke, Marsha Meinders; Linell, David; Moon, Ki Hoon; Oreskovich, Julie A; Betts, Ray; Nadeau, Lynette; Johanneck, Luke; Turos, Mugur; DeRocher, WillThis project was undertaken to advance the knowledge of the beneficial uses of taconite mining coarse tailings (taconite fine aggregate) for thin lift hot mix asphalt (HMA), to facilitate technical information gathering and marketing of such uses and properties, and to encourage the beneficial use of recycled/byproduct materials like durable and wear- and skid-resistant taconite (Mesabi) aggregates, recycled asphalt pavement (RAP), and asphalt shingles. In combination, the use of each is highly desirable because it promotes resource conservation, safety, and energy-saving. Outcomes of this study suggest that Mesabi rock and tailings products show promise as components of 4.75-mm Dense-graded, Stone Matrix Asphalt, and Ultra-Thin Bonded Wearing asphalt mixtures. Laboratory and field investigations of taconite tailings should continue. The Mesabi rock can be incorporated in standard Superpave, SMA, and fine/sand asphalt mixtures in upcoming construction projects. In each case construction and long term field performance should be evaluated. The investigators conclude that taconite-based thin lift HMA mixes that also incorporate RAP should be recognized as an environmentally sound, i.e., combining the use of byproduct and recycled/reclaimed materials, and high-quality option for HMA pavement rehabilitation and preservation. Collectively, the material testing results suggest that thinner wear-course pavements made from appropriately designed taconite-based mixes can match or exceed the service life of conventional MnDOT Level 4 mixtures. If extended service life is realized, then taconite fine aggregate could be a cost-effective choice at end-user locations where high-quality local aggregate sources are lacking or absent. These enhanced performance attributes can add intrinsic value to taconite materials and make them more desirable to use and more cost-effective to transport longer distances, thereby improving and broadening their near- and long-term potential for regional and national highway infrastructure projects.Item Split application of sulfur and potassium and their leaching potential for corn grown on irrigated soils(2013-09) Bonde, Andria JansenIrrigated coarse textured soils have the potential to produce high yielding crops but are also likely to leach out fertilizer nutrients before they can be utilized. Few studies have considered split fertilizer applications of sulfur (S) and potassium (K) on coarse textured soils. Eight fertilizer studies, four S and four K, were conducted to assess how split applications of S and K fertilizers affect plant uptake, corn grain yield, and the leaching potential over the growing season. Each site had four at planting (AP) and four in-season (IS) fertilizer rates applied for a combination of 16 different fertilizer treatments. Various plant tissue, remote sensing readings, and soil samples were taken to assess nutrient availability and movement through the soil profile. Suction cup lysimeters were used in select treatments to monitor soil pore water concentrations. Single or split applications of S and K fertilizers did not increase grain yield. Significant differences among different AP and IS rates were found for early plant and ear leaf S and K concentrations, but these were unable to predict grain yield. Normalized difference vegetation index or SPAD chlorophyll readers did not prove to be indicators of final corn grain yield in either S or K studies. Plant NDVI data was able to predict biomass in K studies. Lysimeter data from S studies suggest increased S concentration towards the end of the growing season but provided no advantage of split application of S fertilizer to avoid S losses. Lysimeter data suggested early season K movement and in most sites and IS fertilizer application had the greatest effect on end of the growing season pore water K concentration. Because of potential early K movement, split applications may be advised for farmers growing corn on coarse textured soils to avoid K losses.