Theses and Dissertations at Montana State University (MSU)
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Item An ecological risk assessment for acid mine drainage from copper-nickel mining in the kawishiwi watershed, minnesota(Montana State University, 2021) Tofte, Zaddy Andrea; Chairperson, Graduate Committee: Scott PowellThe mining of heavy metals such as copper and nickel has been identified as a potential source of acid mine drainage (AMD), which is a consequence of the oxidation of sulfide minerals that produces sulfuric acid due to mine wastes being exposed to air and water. Contamination of AMD to surface waters may pose detrimental effects on aquatic organisms. Accidental releases of process or seepage waters are likely to occur by mining ventures. The Kawishiwi watershed lies over a layered mafic intrusion known as the Duluth Complex, a mineral deposit rich in copper and nickel. Twin Metals Minnesota has renewed the mineral leases looking to develop an underground mine operation adjacently to Birch Lake and the South Kawishiwi River. Therefore, an aquatic ecological risk assessment is necessary to access and protect ecosystems that may be exposed to AMD. My study examined four potential contamination scenarios (A-D) in Birch Lake, Kawishiwi Watershed, Minnesota, based on hypothetical spills and metal concentrations. Concentrations reported in seepage waters from mines or from local sources that share the same mineral deposit or rock characteristics, were chosen to represent realistic scenarios. The concentrations varied for copper from 11 to 0.1 ?g/L and for nickel from 1,580 to 9 ?g/L. The scenarios also accounted for a determined size of spill, which varied from 10 to 0.3% of the total volume of the contact water pond 1. This pond is designated in the Twin Metal Minnesota operations plan to collect the waters from direct precipitation or stormwater that comes in contact with ore or tailings. The purpose of my assessment was to estimate the risks of this contamination to fish species living in the lakes. I used these final concentrations from the proposed scenarios to evaluate if exposure would exceed toxicity endpoints. The risk was assessed using the risk quotient (RQ) method, where the RQ is the ratio of exposure to effect. Risk quotient values < 0.5 are consider below regulatory levels of concern. My results suggest that the toxicity endpoint was exceeded for one of the four contamination scenarios by the most sensitive species: embryos of rainbow trout and bluegill. The contamination scenarios representing the two lowest concentrations for copper and nickel did not suggest levels of concern for either of the fish species. Based on my results, the water volume of Birch Lake would provide sufficient dilution in pollution events that are as much or less than ones represented by Scenarios C and D. Conversely, a spill representing Scenario A would pose risks to fish species exceeding levels of concern, especially to the most sensitive species. My assessment may be applicable when considering the risks that aquatic species could face in the event of a leak or spill of AMD of a sulfide mine in the Kawishiwi Watershed.Item Investigation of microbially induced carbonate precipitation for mitigation of acid mine drainage from coal mining waste(Montana State University - Bozeman, College of Engineering, 2023) Delwiche, Jenna Anne; Chairperson, Graduate Committee: Ellen G. Lauchnor; Adrienne J. Phillips (co-chair); This is a manuscript style paper that includes co-authored chapters.Acid Mine Drainage (AMD) is a serious environmental concern associated with coal mining. Many of the existing methods for addressing AMD are costly and focus on clean-up rather than prevention. In this study, the feasibility of using microbially induced carbonate precipitation (MICP) as an alternative method for mitigating environmental impacts from coal mining waste rock was investigated using laboratory scale experiments. Flow-through column testing showed that MICP can be used to create a calcium carbonate coating on coal waste rock, acting as a barrier between the rock and water. This treatment increased leachate pH, and microscopic inspection indicated that the presence of live bacteria was important for creating a durable coating. The MICP treatment decreased concentrations of heavy metals such as aluminum, barium, beryllium, copper, nickel, zinc, and iron in the leachate, but increased concentrations of vanadium, selenium, molybdenum, uranium, and arsenic. These results indicate that MICP may be an effective technique for mitigating AMD, but additional laboratory and field testing is needed to assess the feasibility of this treatment technology.Item A review of substrates and vegetation in wetlands constructed to treat acid mine drainage(Montana State University - Bozeman, 1995) Tickner, Darcy Nina; Chairperson, Graduate Committee: Douglas J. DollhopfItem Biocatalyzed partial demineralization of acidic metal sulfate solutions(Montana State University - Bozeman, College of Engineering, 1989) Hunter, Robert MichaelItem Evaluation of selected phosphate sources for the control of acid production from pyritic coal overburden(Montana State University - Bozeman, College of Agriculture, 1990) Spotts, EdwardItem Geochemical characteristics of a waste rock repository at a western gold mine(Montana State University - Bozeman, College of Agriculture, 1997) Outlaw, Jason DwayneItem Hydrology of a waste rock repository capping system at the Zortman Mine(Montana State University - Bozeman, College of Agriculture, 1997) Warnemuende, E. A.Item Hydrologic evaluation of tailings covers at the Golden Sunlight Mine(Montana State University - Bozeman, College of Agriculture, 1994) Strong, Murray RandalItem Effects of supplemental organic carbon addition on sulfate reduction and zinc sulfide precipitation using microcosm and bench-scale constructed wetlands in cold climate regions(Montana State University - Bozeman, College of Engineering, 2001) Borden, Deborah JeanItem Effects of acid mine pollution on the benthic macro-invertebrates of the Dry Fork of Belt Creek drainage(Montana State University - Bozeman, College of Letters & Science, 1974) Vandenberg, Raymond James