Browsing by Subject "Mining"

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Apple Valley Sustainability Master Plan
(Minneapolis: Center for Urban and Regional Affairs, 2010) Cedarleaf Dahl, Erik; Jerabek, Erin; Schwartz, J Daniel; Spaulding, Bob; Turner, Mackenzie; Walding, Shawn; Younkin, Kara
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.
A comprehensive alcohol and drug testing policy in the workplace as an intervention in the mining sector
(Journal of Studies in Humanities and Social Sciences., 2016) Maretha, Maree; Lightfoot, Elizabeth; Ananias, Janetta
The abuse of alcohol and drugs can negatively affect the workplace. The testing of workers for substances is a sensitive, yet effective intervention to minimise the percentage of workers who test positively for substance abuse. Little research has been conducted to assess the impact of alcohol and drug testing on the workplace. Thus, this qualitative study, carried out in the mining industry in Namibia, investigates how a comprehensive workplace policy on alcohol and drug abuse can reduce substance abuse among workers during working hours. Data was gathered by means of six focus group discussions and 16 in-depth interviews, incorporating workers from all job grades, as well as community members in a closed mining town. The findings show that the comprehensive alcohol and drug testing policy had a positive impact on reducing the occurrence of substance abuse in the workplace. Since the introduction of both random drug and alcohol tests and fit-for-work testing, fewer workers were testing positively for the presence of substances, and participants noted how workers restricted their substance use specifically because of the testing. A central feature of this particular alcohol and drug testing policy is its provision of substance abuse treatment to workers who tested positively for the presence of substances and the involvement of a social worker hired by the mine, rather than simply a punitive approach. However, findings also show that treatment programs need to be followed up with standard aftercare procedures, such as support groups and training on policies and procedures around alcohol and drug testing, in order to improve worker perceptions and acceptance of policies. Furthermore, prevention efforts were regarded as more cost-effective and proactive than the treatment of substance abuse, and holistic substance abuse training was seen as improving awareness among workers. This paper is dedicated to Maretha Maree – she was a teacher/lecturer, mentor and colleague. Maretha was a lecturer in the Department of Social Work for almost 30 years until her death in November 2013. Over all the years at UNAM, she taught many courses amongst others community work, palliative care, and social work management. The late Maretha will also be remembered for her expertise in substance abuse in Namibia, as chairperson of Namibia’s Drug Awareness Group, she was instrumental in the facilitation and establishment the Teenagers Against Drug Abuse (TADA) groups through Namibia. This paper is also amongst the many scientifi c contributions made by the late Maretha Maree towards substance abuse in Namibia.
The Economics and Logistics of Transporting Taconite Mining and Processing Byproducts (Aggregate): Minnesota and Beyond
(University of Minnesota Duluth, 2007-10) Zanko, Lawrence M
Every year, Minnesota’s taconite mining industry generates over 125 million tons of mining byproducts, a figure that is more than double the entire state’s annual aggregate usage. Since 2000, the Natural Resources Research Institute (NRRI), University of Minnesota, Duluth, has been investigating how these vast quantities of taconite mining byproducts can be used for construction aggregate purposes on an expanded basis. However, if taconite-based aggregate is to be competitive beyond the Mesabi Iron Range, cost-effective rail transport options will be needed, and rail-related economic and logistical barriers must be identified, quantified, and overcome. The reality is, lower value/higher volume commodities like construction aggregates are often economically limited by their distance to market, due to the cost of transportation. Consequently, this study is focusing on rail transport by reviewing/identifying transportation networks, logistics, equipment availability, costs, and potential difficulties associated with moving taconite aggregate through that network. Truck, barge, and Great Lakes shipping are also being addressed. By identifying the key transportation and market-related issues, this study will give potential end-users inside and outside Minnesota a better understanding of how taconite aggregate could be an important alternative to “conventional” aggregate sources. Likewise, taconite producers will have a better understanding of the relative ease or difficulty of marketing and/or moving various types of aggregate, and the potential economic benefit(s) thereof. By improving our understanding of what the supply, demand, and movement dynamics are (and how they interrelate), the prospect for expanded use of taconite aggregate will be enhanced - a development which will ultimately be important for both the economy and the environment, a dual benefit measurable in both a dollars (economic) and tons (resource conservation) sense. This Technical Summary Report describes project activities and progress through October of 2007.
The Economics and Logistics of Transporting Taconite Mining and Processing Byproducts (Aggregate): Minnesota and Beyond
(University of Minnesota Duluth, 2008) Zanko, Lawrence M; Ogard, Elizabeth E; Stewart, Richard D
Exposures to Commercial Asbestos In Northeastern Minnesota Iron Miners who Developed Mesothelioma
(2003) Minnesota Department of Health; Brunner, Wendy; Williams, Allan N; Bender, Alan P
This is primary a public health study on the incidence of mesothelioma in northeastern Minnesota. Its value lies in pointing out human health impacts of mining, and of dumping taconite tailings into the Duluth harbor on the City's drinking water. In both cases asbestos fibers are implicated. Key points linking water resources and human health are extracted and reproduced below. "There is a long history of community concern about a possible link between the mining industry in northeastern Minnesota and the occurrence of cancers and respiratory diseases in that part of the state. In 1973, asbestos-like fibers were found in the Duluth water supply and traced to tailings that had been disposed of in Lake Superior by the Reserve Mining Company. This finding, along with litigation surrounding Reserve's disposal of tailings, prompted studies of the fibers, the effects of ingestion of the fibers, and the morbidity and mortality of iron ore miners, among many other studies. In addition, the Tri-County cancer survey was established by the Minnesota Department of Health (MDH) to monitor cancer rates in northeastern Minnesota. Because of the history of health concerns about mining and the large numbers of people historically employed in iron mining in these counties, the possible relationship between employment in the mining industry and mesothelioma was the primary focus of this study. It was recognized at the outset, however, that at least one other industry unique to northeastern Minnesota significantly contributed to the mesothelioma excess. The former Conwed Corporation plant in Carlton County employed over 5,000 workers between 1958 and 1974, during which time large quantities of commercial asbestos were used in the manufacturing of mineral board and ceiling tile."
Geologic and Stratigraphic Controls of the Biwabik Iron Formation and the Aggregate Potential of the Mesabi Iron Range, Minnesota
(University of Minnesota Duluth, 2009) Severson, Mark J; Heine, John J; Patelke, Marsha Meinders
The taconite mines on the Mesabi Iron Range of northeastern Minnesota generate millions of tons of mined waste rock annually that could potentially be used as aggregate material in road building projects. Paramount to defining potential aggregate horizons within the mined ironformation is an understanding of the stratigraphy as it relates to mined ore units and waste units at each of the respective taconite mines. However, each mine uses a different submember terminology to designate the various ore and waste horizons. The major emphasis of this investigation was to produce a stratigraphic “Rosetta Stone” of the Biwabik Iron Formation that ties the stratigraphy and differing submember terminology of one mine to all of the other mines on the Mesabi Iron Range. Toward that end, the Natural Resources Research Institute (NRRI) looked at core from over 380 drill holes, and some mine exposures, in the central and western Mesabi Iron Range (Biwabik to Coleraine, MN area) to develop a stratigraphic system that links all of the mined ore and waste submembers. The methodology used in this investigation was to log multitudinous deep drill holes from a single mine, hang all of the drill holes on a common datum (bottom of the Lower Slaty member), and then correlate all of the submembers, as used by that particular mine, making note of bedding features and other unique features that define a particular submember. This same system of “logging, hanging, and correlating” was done at each of the taconite mines (seven different mines/areas along the Mesabi Iron Range) to better understand each mine’s submember terminology. The hung stratigraphic-sections from each mine were then used to collectively make generalized stratigraphic columns for each of the mines. These stratigraphic columns were then added to the “Rosetta Stone” (Plate II of this report) that is used to illustrate how the submembers at one mine correlate with similar submembers at all of the other mines. In the end, this investigation identified 25 major “Rosetta” units that define the stratigraphy of the Biwabik Iron Formation that can be used to link together all of the differing submember nomenclatures from the various taconite mines. This division of the iron-formation into 25 major units, based primarily on their overall bedding characteristics, is applicable to only the central and western Mesabi Iron Range and does not include the more highly metamorphosed iron-formation of the eastern Mesabi Iron Range, e.g., to the east of Aurora, MN.
The History of Minnesota and Tales of the Frontier
(1900) Flandrau, Charles E
This is a historical document with some anecdotal historical information about the early history of the mining industry and about Native communities in the St. Louis River watershed, told from the perspective of a non-Native historical figure. Much of the narrative has been embellished. This book has little value in describing water resources and people in an accurate, historical manner.
Hydrology and Water Quality of the Copper-Nickel Study Region, Northeastern Minnesota
(1980) Siegel, Donald I; Ericson, Donald W
This 35-year old hydrologic study documents conditions in the Cu-NU region of Minnesota’s Iron Range. It is primarily a technical report, but its main value is the baseline data provided, and that it contains a water budget for the area. It’s primary message for decision-makers is that “the introduction of trace metals from future mining to the ground-water system can be reduced if tailings basins and stockpiles are located on material of low permeability, such as till, peat, or bedrock." Key segments are extracted and reproduced below. Abstract: "Data were collected on the hydrology of the Copper-Nickel study region, to identify the location and nature of ground-water resources, determine the flow characteristics and general quality of the major streams, and determine the potential effects of mining copper and nickel on the hydrologic system. Ground-water investigations indicate that water generally occurs in local flow systems within surficial deposits and in fractures in the upper few hundred feet of bedrock. Availability of ground water is highly variable. Yields commonly range from only 1 to 5 gallons per minute from wells in surficial materials and bedrock, but can be as much as 1,000 gallons per minute from wells in the sand and gravel aquifer underlying the Embarrass River valley. Except over the mineralized zone, ground water in the surficial deposits is a mixed calcium magnesium bicarbonate type. Ground water over the mineralized zone generally has both a greater percentage of sulfate, compared to bicarbonate, and concentrations of copper and nickel greater than 5 micrograms per liter. "Surface-water investigations indicate that the average annual runoff from streams is about 10 inches. Plow characteristics of streams unregulated by industry are similar, with about 60 percent of the annual runoff occurring during snowmelt in April, May, and June. Flood peaks are reduced in the Kawishiwi River and other streams that have surface storage available in onchannel lakes and wetlands. These lakes and wetlands also trap part of the suspended-sediment load. Specific conductance in streams can exceed 250 micromhos per centimeter at 25° Celsius where mine dewatering supplements natural discharge. "Between 85 and 95 percent of the surface water used is for hydroelectric power generation at Winton and thermo-electric power generation at Colby Lakes. Mine dewatering accounts for about 95 percent of the ground-water used. Estimated ground-water discharge to projected copper-nickel mines ranges from less than 25 to about 2,000 gallons per minute, depending on the location and type of mining activity. The introduction of trace metals from future mining to the ground-water system can be reduced if tailings basins and stockpiles are located on material of low permeability, such as till, peat, or bedrock."
The Minnesota Regional Copper-Nickel Study 1976-1979, Volume 1: Executive Summary
(1979) Minnesota Environmental Quality Board
This is a comprehensive, clearly-written document summarizing potential biophysical and socioeconomic impacts of copper-nickel mining in Minnesota. Special attention is paid to impacts on water resources. Relevant sections are reproduced in their entirely below, not only for historical interest but because of predictive power. Summary: "The Minnesota Environmental Quality Board's Regional Copper-Nickel Study is a comprehensive technical examination of the environmental, social, and economic impacts associated with the potential development of copper-nickel sulfide mineral resources of the Duluth Complex in northeastern Minnesota. This executive summary of the 5 volume, 36 chapter report presents some of the major findings of the Study, but in order to get a complete picture of the complex issues associated with exploiting this valuable mineral resource, the entire document should be examined. In addition to this report over 180 technical reports, extensive environmental monitoring data files, special sample collections, and other information resources were compiled by the Study" (n.b. these documents were not reviewed as part of this current desk review). Consistent with directions from the Minnesota Legislature, the Regional Copper-Nickel Study presents technical findings but does not make policy recommendations based on these findings." "To allow for a discussion of the potential environmental and socio-economic effects of copper-nickel development, an area of approximately 2100 square miles was designated as the Regional Copper-Nickel Study Area (or simply, the Study Area). This area contains Virginia in the southwest corner and Ely in the northeast corner. The major copper-nickel deposits of interest occur along the Duluth Gabbro Contact, in a band three miles wide and fifty miles long (the Resource Area); however, additional deposits may extend beyond this band. The Water Quality Research Area, which includes the complete watersheds of 14 streams of interest, is shown in Figure 2. Waters north of the Laurentian Divide are part of the Rainey River Watershed, which includes a portion of the Boundary Waters Canoe Area, and whose waters eventually drain into Hudson Bay and the North Atlantic. Waters south of the Divide are a part of the St. Louis River Watershed which drains into Lake Superior and eventually into the Atlantic Ocean via the St. Lawrence River.” "Historically, the exploitation of base metal sulfide resources (such as copper-nickel resources) throughout the world has been accompanied by the significant degradation of the quality of water resources and the destruction of aquatic and terrestrial biota m the vicinity of such developments. Acid mine drainage, toxic heavy metals contamination, erosion, sedimentation, increased salinity, and other water pollution problems associated with mining were common. The nonferrous minerals smelting industry (principally copper, lead, and zinc) has also been a major source of manmade air pollutants. Until new technology has been developed to minimize many of these impacts, adverse impacts of past practices continue to cause close scrutiny of new mining proposals.” Water Quantity (Volume 3-Chapter 4). "Surface water is abundant in the Water Research Study Area due to high surface runoff. Average annual runoff in the region is about 10 inches. The Water Research Study Area includes 360 lakes larger than 10 acres, in addition to 14 small rivers and streams. Nearly 75 percent of the Water Research Study Area, and an even larger proportion of the surface water is north of the Laurentian Divide. North of the Divide, lakes are more numerous and larger, and the volume of stream flow is greater because a larger area is being drained. Because some of these waters are inside the BWCA, not all of the water north of the Divide is directly available for use. Annual average flow for 12 streams studied by the U.S. Geological Survey for the Study ranged from 23 to 1,027 cubic feet per second (cfs). High flow generally occurs after heavy precipitation and following the spring snowmelt. Average low flow for seven days is 2 to 186 cfs compared to an average high flow of 87 to 4,763 cfs. Ground water yield is generally low, limited by the low permeability of the Area's bedrock and the often shallow overlaying glacial deposits. Yields generally average less than 5 gallons/minute. Three relatively small areas have high volume aquifers yielding up to 1,000 gallons/minute: the Embarrass Sand Plain, the Dunka River Sand Plain, and the local fractured and leached bedrock areas in the Biwabik Iron Formation.” "Current industrial use of surface water is primarily for electric power generation. Mine-pit dewatering is the greatest groundwater use. At current levels, water use does not cause significant impacts on the region's water resources, although withdrawal from some streams must be reduced during low flow. Surface water, including some of the large on-channel lakes (e.g. Birch Lake), could supply large water users, al though storage may be required for certain streams. The Embarrass River Valley aquifer is the only identified groundwater source in surficial materials that could supply large water users.” Water Quality (Volume 3-Chapter 4). "Because of the large number of streams and lakes in the Study Area, the value of high quality water which supports a significant recreational and wilderness resource of the state and the nation, and the recognized historic relationship between base-metal mining and water pollution, a major responsibility of the Regional Copper-Nickel Study was the collection of baseline surface and ground water quality data (note: data tables and figures and not reproduced). "The quality of the region's water resources is generally very good except for several streams with watersheds affected by extensive taconite mining activities, and for groundwater either from glacial till or wells near the Duluth Gabbro Complex sulfide mineralization. Streams draining largely undisturbed watersheds can be described as containing soft water, having low alkalinity, low total dissolved solids, low nutrients, high color, very low trace metals concentrations, and low fecal coliform counts.” "Streams draining disturbed watersheds (Partridge, Embarrass, Upper St. Louis rivers south of the Laurentian Divide, and the lower Dunka River and Unnamed Creek north of the Divide) would be considered to contain moderately hard to hard waters, with elevated dissolved solids, nutrients, and trace metals concentrations relative to undisturbed watersheds. Color and fecal coliform concentrations are not significantly different in the two watershed classifications. Most water quality parameters tend to be much less variable in undisturbed streams as compared to disturbed streams. The quality of the lakes studied is variable though similar to the quality of undisturbed streams. However, lake values may be less meaningful for determining baseline concentrations than values in streams because of the limited number of samples.” "In general, concentrations of most chemical constituents are higher in the groundwater than in streams and lakes of the area. Groundwater from wells proximate to the Duluth Gabbro contact were found to have higher levels of trace metals and sulfate than wells located at a distance from the contact. Phosphorus and nitrogen are the major nutrients in aquatic systems. Concentrations of both nutrients in study streams are at the low end of the range of values for U.S. streams. Variations in nutrient levels exhibited no clear trends between headwater and downstream stations or between small and large watersheds. Highest concentrations of nitrogen were found downstream from mining operations where blasting compounds containing nitrogen are used. In lakes, nutrient parameters are closely associated with the activities of aquatic organisms. Higher levels of available nutrients encourage greater biological productivity. The ratio of nitrogen (N) to phosphorus (p) can be used to evaluate which of these nutrients limits algal productivity. Lakes with a N:P ratio greater than 14 are considered to be limited by phosphorus. Within the Study Area, median N:P ratios ranged from 14 to 60, and half the lakes studied had ratios greater than 25. Overall concentrations of both nutrients were at the low end. Median values for both nutrients were higher south of the Laurentian Divide than north of it. The most productive lakes were all headwater lakes, usually shallow, and surrounded by extensive bog and marsh areas.” "A major concern related to copper-nickel development is levels of heavy metals in surface waters. At background stream stations, copper, nickel, and zinc levels are generally very low, with median concentrations of copper and zinc in the range of 1-2 ug/liter and nickel around 1 ug/liter. Other trace metals of biological importance (As, Cd, Co, Hg, and Pb) have median concentrations significantly below 1 ug/liter. There is little variability in the levels of arsenic, cobalt, cadmium, mercury, titanium, selenium, and silver across almost all surface waters monitored. As expected, iron, manganese, copper, nickel, zinc, lead, fluoride, and chromium concentrations in streams are significantly higher in disturbed watersheds than in undisturbed areas. The dynamics of metals in lakes are somewhat different from those in streams because the large surface area of bottom sediments with their varying oxidation reduction potentials complicates the picture. Lakes can act as sinks for metals (as is the case with iron at Colby Lake) so that the chemistry of out flowing waters is different from that of inflowing waters. Large lakes may exhibit variability in the concentration of metals within the lake itself (as is the case with nickel in Birch Lake). Similar to streams, iron,' aluminum, and manganese were the most elevated metals in the Study Area lakes. Copper, nickel, and zinc have median levels between 1 and 2 ug/l, whereas arsenic, cobalt, and lead have median levels of 0.6,0.4, and 0.4 ug/l, respectively. Cadmium levels were an order of magnitude (10 times) lower than those for arsenic, cobalt, and lead. The greatest variabilities in concentrations were exhibited by manganese, zinc, cadmium, and aluminum, with arsenic the least variable metal.” "Water quality standards and criteria for many parameters have been adopted or are proposed for adoption by the Minnesota Pollution Control Agency or the U.S. Environmental Protection Agency (EPA). Recommended levels for cadmium, color, copper, iron, lead, manganese, mercury, nickel, nitrogen (as N02 + N03), pH, specific conductance, sulfate, and zinc were exceeded in one or more of the streams monitored. In most cases, these elevated levels occurred in Unnamed Creek, which is affected by mining (see discussion of Unnamed Creek below). The region's streams and lakes have naturally high color levels.” "All streams which were monitored exceeded the EPA water quality criteria for mercury (0.05 ug/liter). The median concentration of mercury for all streams monitored was 0.08 ug/liter with a range of 0.01-0.6 ug/liter. Standards for mercury are based on U.S. Food and Drug Administration guidelines for edible fish. High mercury levels have been found in fish from some of the area's lakes and streams. Because acid precipitation is a potential problem, the quality of precipitation in the Study Area was monitored at several sites. Seventy-seven percent of the samples (41) had a pH less than 5.7, which means that most of the precipitation measured can be considered acidic. Fifty percent of the samples had a pH of 3.6 to 4.4. The geometric mean pH of samples collected in the area was 4.6. These values are comparable to, or even less than values measured in areas of the world where ecological damage has already occurred. Measurements by the Regional Study indicate that the present annual sulfate deposition rate (wet plus dry) across the Study Area is from 10 to 20 kg/ha/yr (9 to 18 lbs/ acre/yr). Atmospheric dispersion modeling indicates that regional sources of S02 are not major contributors to depressed acidity of precipitation and suIfate deposition in the region. This in turn indicates that out-state and out-of-state sources, possibly as far away as St. Louis, Chicago, and Ohio Valley areas, are likely the major cause of acid rain and sulfate deposition in northeastern Minnesota.” "If the patterns of increasingly acidic precipitation continue, it is likely that many of the poorly buffered small streams will have noticeable decreases in aquatic populations (such as fish) during and following spring melt.” "Stream systems are very sensitive because the flush of water from spring snowmelt can represent a majority of the water that the stream may carry through the whole year. Recovery from these episodes may be expected to be fairly rapid (i.e. within months) unless or until the sources of recolonizing organisms are themselves affected (i.e. well buffered lakes or large unaffected streams). Recovery would be very slow once the source areas are affected. The effects of acid precipitation on vegetation range from damage to leaves to increased susceptibility to disease and death (see Volume 4-Chapter 2). A direct causal relationship between acid precipitat ion and reduced forest productivity measured by growth remains to be demonstrated. However, research suggests that acid precipitation is probably a cause of reduced forest growth. Because acidic precipitation and sulfate deposition are primarily related to air pollution sources outside the region and are projected to increase significantly over the next 10-20 years, acidification may represent a serious threat to the ecosystems of northeastern Minnesota, even if copper-nickel development does not occur. Long-term changes in the aquatic communities are probably already underway due to the general decrease in the pH of precipitation and thereby of surface waters in the Study Area. Because the decrease in pH will likely be slow, measurement of biological effects would require intensive long-term monitoring. During this period of decreasing pH, the overall productivity and diversity of the aquatic communities can be expected to decrease.” "One crucial parameter that was monitored is the water's buffering capacity-- its ability to regulate pH changes due to acid inputs from atmospheric deposition or leaching. The resistance to pH change is a function of the type of acid input (i.e. strong or weak acids) and the type of chemical components in the receiving water which can assimilate or bind the hydrogen ions. Calcite saturation indices (csr) were calculated for all study lakes and 30 lakes in the BWCA to measure this buffering capacity. Lakes with a csr less than 3.0 are well buffered; lakes with an index between 3.0 and 5.0 are poorly buffered with the possibility that acidification may already be occurring; and an index over 5.0 indicates lakes with little or no buffering ability and a strong possibility that severe acidification has already occurred.” "The poorly buffered lakes in the region are with few exceptions headwater lakes. This may be explained by the fact that buffering is a function not only of atmospheric processes, but also of watershed geology. The chemistry of headwater lakes often reflects that of precipitation, with watershed contributions to lake chemistry assuming secondary importance. As one proceeds from headwater to downstream lakes 1.U the Study Area, the ability of the lakes to assimilate hydrogen ions generally increases. Headwater areas of the region (which include half the BWCA lakes studied) are generally not well buffered and have limited capacities to assimilate existing acid loadings. Some of the lakes sampled during the study which may be the earliest to be affected by acidic precipitation include: Clearwater, August, Turtle, One, Greenwood, Perch, and Long lakes. These lakes have Calcite Saturation Indices above 3.0. Headwater streams are generally poorly buffered, in part because their water quality is also dependent upon the quality of precipitation.” "Two unique water quality conditions have been identified in the Study Area which are directly related to the presence of copper-nickel sulfide mineralization. In one of these cases, human disturbance of this mineralization has accelerated the chemical/physical weathering (leaching) of this material. Filson Creek, located in the northeastern part of the Study Area adjacent to the BWCA, flows naturally over exposed mineralized gabbro. Within the Filson Creek watershed, total concentrations of copper and nickel 10 the year 1977 generally increased from headwater locations to Filson's point of discharge into the South Kawishiwi River. Total nickel concentrations measured in Filson's headwaters were, except for one sample, less than 1 ug/liter, while the mean nickel concentration near the mouth of the watershed was 3 to 5 ug/liter. The smaller copper and nickel concentrations at Filson Creek headwater locations reflect the smaller percentage of sulfide bearing material in the till and the greater distance from the mineralized contact zone. The elevated metal values measured in Filson Creek may not be completely due to natural weathering of sulfide minerals. Prior to 1977, considerable mineral exploration activities occurred, including the taking of a bulk surface mineral sample. Subsequently, a small volume surface discharge was discovered at the foot of the bulk sample site with elevated metals levels (10,000 to 13,000 ug/l Ni, 360 to 1,000 ug/l Cu, and 190 to 5300 ug/l 2n). This discharge enters a small tributary of Filson Creek and raises the nickel and copper concentrations by about 9 ug/l and 5 ug/l, respectively. This change in trace metal concentrations is not sufficient to result in measureable biological changes in the Creek.” "In the other unique case, a small watershed (Unnamed Creek) which drains into Birch Lake at Bob Bay contains several wastepiles containing mineralized gabbro from a nearby taconite mining operation (Erie Mining Company's Dunka Pit). The large surface area of the waste rock facilitates the chemical weathering process. Surface seeps containing elevated concentrations of sulfates and trace metals (especially nickel) are present. The seeps flow into Unnamed Creek where the influence of this disturbance on water quality is obvious. Median nickel levels in Unnamed Creek were 85 ug/l, compared to 1 ug/l in undisturbed streams (Table 4). Extensive field studies conducted in this watershed have demonstrated that extensive disturbance of the mineralized gabbro without corrective mitigation can result in significant water quality degradation. The magnitude of the potential impacts in this specific case is largely mitigated by natural chemical processes involving adsorption, chemical complexation, and precipitation due largely to the presence of a bog in the watershed. The metal concentrations measured at Bob Bay would be significantly higher if not for the effect of the bog. However, the bog is showing some signs of stress and its beneficial effect on water quality may not continue for long.” Environmental Impact Assessment: Water Use "Water is required in significant quantities as a transport medium for the ore during concentration and for tailing disposal. Additional water is required in the smelting and refining phase for cooling and other purposes. Precipitation partially offsets the major water losses coming from evaporation losses coming from evaporation from tailing basins and water trapped between particles in tailing basins. However, fresh makeup water (estimated to average 0.76-1 b ill ion gallons per year) will be required for all three integrated copper-nickel development models (Volume 2-Chapter 5). Water requirements will vary significantly on a seasonal and annual basis.” "A good water management system is designed to manage and store runoff and seepage on the site (around waste piles, tailing basins, and elsewhere). The specific site and the design of the system will determine whether periodic discharges of waste water will be necessary during periods of above average precipitation. Because of the fairly continuous demand for water and the varying supply of water in lakes and streams in the area, it is estimated that significant water storage (10,000 to 15,000 acre-feet) will be necessary for use during dry periods. This water storage could be supplied by the tailing basin and/or reservoirs. Storage requirements for makeup water supply and containment of polluted water could increase land requirements by 2,000 to 3,000 acres.” "Increased demand for water could become a source of conflict if waters tributary to the BWCA are appropriated for copper-nickel development and if the waters are also diverted for taconite development, such as the Upper St. Louis and Partridge river watersheds. These issues could be considered prior to issuance of a DNR permit which s required for water appropriation. However, if both taconite expansion and copper-nickel development proceed in northeastern Minnesota, a regional comprehensive water management plan and perhaps a cooperative industrial water supply system may need to be considered.” "Quality of tailing water during the operating phase 1S primarily controlled by the concentrating process water. This water is largely recycled and should not be a significant heavy metal pollution source. Seepage can also be collected and recycled if necessary. Elevated levels could occur during the post-operating phase or if more sulfides are deposited in the basin than projected. Local variation in ore mineralogy could result in pockets of tailing having much higher sulfide concentrations which could cause localized leaching problems. Due to limited research on tailing water quality, the unknowns involving the quality of runoff and seepage from a tailing basin are greater than those associated with waste rock piles and create another source of significant risk involving future copper-nickel water management decisions.” "Mine dewatering can also contribute heavy metals, the amount depending upon the quantity of water from precipitation and groundwater sources that must be removed and the metal sulfide content of the mine. No precise conclusions can be made about expected levels of heavy metal release from this source. Smelter and refinery waste water 1S not as significant an issue as waste piles. Production of these waste waters 1S dependent on facility design and operation, and there appears to be no significant post-operational concerns.” "Treatment methods are available to reduce heavy metal concentrations in these waste waters to levels where biological impacts are not expected. Effluent water quality models for impact assessment purposes were developed (Volume 3-Chapter 4) based on the best data available from field and laboratory results, but this information is not sufficient to allow precise statements on the quality of water produced from copper-nickel water pollution sources or on the effectiveness of reclamation practices for specific effluent parameters (e.g. suIfates, trace metaIs, processing reagents). For example, information strongly suggests that runoff from waste piles will contain elevated heavy metals and dissolved solids concentrations as compared to background surface water quality. Heavy metals could be 500 to several thousand times higher than natural water quality levels and sulfates could be ten to several hundred times higher.” "These models reflect an assumption that acid mine drainage problems will not occur because of the natural buffering capacity of the waste materials. If this assumption IS wrong and acid conditions do occur, then projections of water pollution will be significantly underestimated because, as the pH becomes acid, there are dramatic increases in the amount of heavy metals leached from the waste significantly affects whether a metal will be in an aqueous phase (and highly mobile) or in a solid phase.” "Treatment of large amounts of runoff to remove heavy metals to existing background levels may be prohibitively expensive. Additional research is necessary in order to make accurate predictions about effluent quality and the effectiveness of various controls. Cost and time constraints will likely require that the first mining activities proceed without this predictive capability.” Heavy metals have adverse effects on aquatic organisms, the extent depending upon the type of metal (or combination of metals), organism tolerance, and water chemistry (Volume 4-Chapter 1). For example, cold water fisheries are generally more susceptible to heavy metal pollution than warm water fisheries." No mention is made of impacts on wild rice stands.
On-Line Measurement of Moisture Content of Iron Ore Slurries
(2014) Gao, Feng; Davis, Richard A
This report presents a method of measuring moisture content in iron ore slurries using the application of microwave. The composition of iron ore slurries consists of magnetite, hematite, calcium carbonate, magnesium carbonate, siderite, alumina, silica, and water. When being placed in an electromagnetic field, interactions will happen between the slurry components and the field. Permittivity ϵ^* is the main parameter to describe these interactions. Since water has the largest dielectric constant compared with other materials, the water content of the material can be estimated from measured permittivity values. For each species, attenuation and microwave phase shift are two intermediate functions related to permittivity, temperature and bed depth when a microwave is passing through particles on conveyor belt. According to theory, a linear model is expected between the materials’ moisture content and the ratio of attenuation and phase shift.
Outdoor Recreation in the Regional Copper-Nickel Study Area
(1978) Webb, Sara
This 35-year old study primarily discusses non-Indian recreational use of public and private lands in the Cu-Ni region of Minnesota’s Iron Range. This recreation-oriented study does not specifically note Native American use of study area lands except for very indirect references to gill-netting and wild ricing. It has a strong focus on human use of water resources in the region, but does not investigate potential impacts of increased recreational use, mining, or other anthropogenic activities with potential to affect condition of these resources. The study abstract and key segments are extracted and reproduced below. Abstract: “Geographic patters of outdoor recreational use in the Copper-Nickel Study Area were investigated as part of a study of potential impacts of copper-nickel mining in Northeastern Minnesota. With the objective of characterizing patterns of recreational use of facilities, water bodies and public lands, interviews were held with thirteen land use managers and others familiar with the study area. Findings from this interview program together with past recreation research provide a data base on existing recreational use necessary for to impact analysis. Numerous public and private recreation facilities are located along Study Area lakes and streams. Outside facilities, public and some private lands are used for diverse land-based activities when afforded road, trail, or surrogate trail access; old logging roads serve this function in the most heavily-used areas, although some activities such as and winter camping rarely occur in recently logged zones. Dense settlement and lowland bogs restrict access by most land-oriented recreationists. Water-based recreation is concentrated on large, deep lakes in the Study Area's northern half. Part of the Boundary Waters Canoe Area (BWCA), a national wilderness area, lies within the Study Area's north boundary. Canoeists and fishermen use BWCA lakes heavily. Dozens of smaller lakes throughout the Study Area serve Iess diverse but sometimes more intensive recreation functions. Only a few lakes lack any recreational use; most are quite small and lack access or recreation resources. Most Study Area streams have limited recreational use because of low water levels, with the exception of two rivers, the Kawishiwi and the St. Louis River. Three general types of outdoor recreation can be distinguished: facility -based recreation), dispersed land-based recreation, and water-based recreation. To spare the time and expense of primary field surveys, a program of interviews with thirteen land managers such as conservation officers and foresters was designed, using Spradley's interview method. Key points: ‘Outdoor recreation in all forms is dependent upon access: roads, trails, and public lands. The region is covered with an extensive network of land management units at various levels. Land-based recreation use relates closely to the area's logging history and logging roads. Lake, stream, road and facility use must be carefully evaluated before siting decisions about mining and recreational use are finalized.’
Oxidized Taconite Geological Resources for a Portion of the Western Mesabi Range (West Half of the Arcturus Mine to the East Half of the Canisteo Mine), Itasca County, Minnesota - A GIS-based Resource Analysis for Land-Use Planning
(University of Minnesota Duluth, 2001) Zanko, Lawrence M; Severson, Mark J; Oreskovich, Julie A; Heine, John J; Hauck, Steven A
Public Comment Form about Mining in the Lake Superior Basin
(2013-12) Lake Superior Binational Program
This is a 291-page raw data summary of comments downloaded from Survey Monkey, and published on the LSBF website. The pdf is undated. The LSBF website contains a short article about the survey, noting that the survey was open for public commentary from March 15 to July 31 2013, and that nearly 1,600 individuals provided comments. There were 45 questions posed to respondents. Some key findings relevant to mining and water resources are extracted and reproduced below. “When asked if there should be specific criteria to prohibit mining activities in environmentally or culturally sensitive areas, 64.9 % said yes, 18.8% said mining should not be restricted in any areas. “When asked ‘Which of the following statements best describes your opinion about mining operations in the Lake Superior basin?’ the most picked response was ‘I do not support any new mines in the Lake Superior basin,’ (38.8% response rate) followed by ‘I support mining operations that can be done using proven responsible management practices that minimize environmental damages’ (25.8% response rate). “When asked is there should there be a moratorium on new mining activity in the Lake Superior basin until it can be proven that new mines won’t pollute surface and groundwater, 63.4% said yes, and 31.8% said no.” Among other results, 68% felt that mining should be restricted in areas where culturally significant food is harvested or grown. 76% felt that mining should be restricted where wetlands have international significance or in locations with endangered plants or animals. 70% felt that mining should be restricted in areas with historic importance. 96% disagreed that taxpayers should pay for clean-up and restoration of damages; while 95% felt that mining companies should pay for these costs. 91% felt that open public meetings should be held to inform the public about mining company compliance. 89% want disclosure of chemicals used in the mining process.”
Regional and Local Geologic and Geochemical Controls on Industrial Clay Grades between Granite Falls and Redwood Falls, Minnesota
(University of Minnesota Duluth, 2004) Heine, John J
Geologic investigations and industry exploration work prior to this study had focused on the area east of Redwood Falls, MN, where many outcrops of kaolin-bearing materials had been located. This study was initiated to examine the area between Redwood Falls and Granite Falls, MN, in order to determine the potential for large deposits of kaolin-bearing materials. One active kaolin mine and one prospect were located in this area during the study, but most of this area had been largely unexplored.
Regional Copper-Nickel Study : Plant Diseases Affecting Forest Trees in Northeastern Minnesota's Regional Copper-Nickel Study Area
(1978) Zeyen, Richard J; Groth, James V
This report presents a series of tables of tree diseases in the region, as well as factual narrative descriptions. The document contains a table of common plant diseases for the region. The remainder of the report describes a variety of tree diseases and their symptoms and appearance. No conclusions or recommendations are included. The abstract and summary points are extracted and reproduced below. "This report is based upon lists of major vegetation community types, compiled for a preliminary study of the Regional Copper-Nickel Study Area. Only dominant plant species, as determined by releve techniques, have been included in the discussion of diseases. The intent of this report is to present a brief survey of the major diseases caused primarily by biotic agents. The information was obtained from general references and from personal observations of the diseases of the area over the past 11 years. The report is divided into two parts: (1) a comprehensive table of diseases recorded in the area and their causal agents (Table 1), and (2) brief descriptions of 25 diseases of exceptional economic or aesthetic importance."
Required Metallic Exploration, Mining, Processing Permits in Minnesota - The Who, What, Where, and When to Non-Ferrous Metallic Mine Permitting
(University of Minnesota Duluth, 2002) Severson, Mark J
In Minnesota, there exists a framework for establishing a new, metallic, non-ferrous mine that involves a process of environmental review and application for various mine-related permits. However, to date, no non-ferrous metallic mines have been developed, and the mine permitting process in Minnesota remains untested. This report is intended to outline each of the permitting steps and to assemble, under one cover, contact numbers and addresses for each of the regulatory agencies that are involved in the process. It is important to stress that this document is intended to serve as only a rudimentary guide in pointing out what types of permits could be anticipated and the minimal length of time (under optimal conditions) that could be required before the mine-related permits are granted. This document is only a “road map” that shows the possible paths for permitting a new metallic mine - it should not be used as a substitute for contacting the various regulatory agencies. The permitting process for a non-ferrous metallic mine in Minnesota involves dealing with several agencies that include: 1) Minnesota Department of Natural Resources (Division of Lands and Minerals, Division of Water, and Office of Budget and Management Services: Review Section); 2) Minnesota Pollution Control Agency (both Air and Water divisions); 3) United States Army Corps of Engineers; 4) local government units; and 5) possibly the United States Forest Service (depending on the location of the mine site). Other agencies that are involved in the process, either directly or indirectly, are also discussed in this report. Although environmental regulations are strong, each of these agencies are willing to work together to help guide mining companies through the environmental review and permitting process to allow for responsible development in an environmentally safe manner. An environmental review, consisting of a Scoping Environmental Assessment Worksheet (EAW) and Scoping Decision, followed by an Environmental Impact Statement (EIS), is mandatory and is one of the first actions that must be completed before any mine-related permits can be granted. There are several background studies, such as waste characterization and other monitoring studies, that will need to be either completed or initiated prior to beginning the environmental review. Concurrent with the environmental review, action will need to be taken on applications for at least eight major permits. Most of these permits will need to be obtained before starting construction of a new mine and auxiliary facilities and include: 1) Permit to Mine (accompanied by a Wetland Replacement Plan); 2) Part 70 Air Quality Operating Permit and NSR Construction Permit; 3) NPDES/SDS Wastewater Permit(s); 4) Section 404 Permit for disturbances to wetlands; 5) Water Appropriation Permit(s); 6) Public Waters Work Permit; 7) Dam Safety Permit; and 8) NPDES/SDS Storm Water Permit for Construction Activity. Action on the first four permits should begin early in the process as some of these permits could take up to 0.5-2.0 years before decisions can be made - decisions on the permits are held in abeyance until a decision is made on the adequacy of the EIS. The purpose of the EIS is to inform the regulatory agencies of possible alternatives that they need to consider when making decisions on whether to grant or deny the mine-related permits. In addition to these permits, another major permit that could be required is a Lease to Mine, obtained from the Bureau of Land Management/United States Forest Service- if the mine site is located on Federal mineral rights. In summary, there are numerous actions that must be initiated and completed before a nonferrous metallic mine can be permitted in Minnesota. These actions include: pre-application background studies, environmental review (scoping EAW and EIS), permit applications, public comment periods, agency comment periods, and finally, decisions on the permits. Under favorable conditions all of these actions could be achieved in 2.5 to 3.0 years. It is up to the proposer to be organized, persistent, professional, and sensitive to public concerns. Each of the regulatory agencies stress that the project proposer contacts them early, hire a competent consultant, and keep them and the public informed of their actions.
Responsible Mining in the Lake Superior Basin
(2013) Lake Superior Binational Program
The Lake Superior Binational Forum drafted a statement on responsible mining, with recommendations for future mining projects, which are summarized in this document. The statement aims at a “zero discharge” principle. The Forum held three public meetings to gather input for the statement. Key excerpts are reproduced below: “Responsible Mining Should: A. Meet or exceed the provisions of the Great Lakes Water Quality Agreement of 2012 between Canada and the United States in: 1. Adopting the goal of zero discharge and zero emission of persistent bioaccumulative toxic substances in the basin, thereby preventing further degradation of the ecosystem. 2. Anticipating and preventing pollution and other threats to water quality in the Great Lakes to reduce overall risks to the environment and human health. 3. Incorporating the precautionary approach, as set forth in the Rio Declaration on Environment and Development, that “Where there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation.” 4. Incorporating the “polluter pays” principle, as set forth in the Rio Declaration on Environment and Development, “that the polluter should bear the cost of pollution.” 5. Applying innovation – considering and applying advanced and environmentally-friendly ideas, methods and efforts to prevent environmental problems. 6. Considering social, economic and environmental factors, including assessment of full life cycle costs and benefits, and incorporating a multi-generational standard of care. B. Be clear and transparent with regulatory agencies, affected communities, and the public, while fostering cooperation with relevant agencies and the greater public. C. Carry out rigorous environmental assessment of all aspects and phases of the mining and milling process, including potential future expansion of mining activities. Public opinion and advice should be incorporated where possible, and the assessment process should explain why other public proposals were not incorporated into the final decision. D. Recognize that short-term mining operations can have long-term legacies, so approved plans should secure funding for staffing, monitoring, prevention, and repair of mining sites after closure. E. Contribute to the local, regional, and national economy through a fair wage, salary, and benefit structure, and in paying all taxes assessed by government agencies in each jurisdiction in which it operates F. Respect private and other land rights and where applicable compensate land owners for losses of value, and land users for losses of opportunity.” The document also contains nine recommendations for future mining operations, briefly summarized as follows: 1. Develop a common set of criteria for use by governments, NGOs and industry to guide the permitting process. Currently public agencies use different criteria in each state. 2. Avoid mining in places with high environmental or social/cultural value. 3. Improve public participation by stakeholders in the environmental assessment process through the collection of adequate baseline data; consideration of potential worst-case scenarios; and independent third-party review processes. 4. Water quality objectives that are consistent with the LAMP should be developed. 5. Overburden and tailings should be discharged into water bodies or wetlands; acid-generating materials should be segregated; and hazardous materials plans should be made public. 6. Companies should make atmospheric emission reports. Environmental assessments should consider greenhouse gas emissions from mining operations. 7. Companies should set aside financial resources for the exploration phase to cover clean-ups, reclamation and long-term monitoring. The public should have the right to comment on the adequacy of these resources and reclamation activities. 8. The public should have the right to access monitoring and periodic technical reports during the life of the mining operation; and to do independent third-party review of the process. 9. Companies should have a reclamation plan with resources set aside for each operation. Mined areas should be re-contoured and stabilized. 10. Citizen participation and oversight are important elements listed under “social impacts and decision making,” including the engagement of Tribal Nations, First Nations and Metis. 11. Research is needed on the cumulative and indirect effects of mining; climate change and mining impacts; and human health research, including impacts on people, fish and wild rice.
Stream and Wetland Biological Survey
(University of Minnesota Duluth, 2005) Breneman, Dan
A biological monitoring survey was conducted on four stream sites and two wetlands in the vicinity of a proposed mining operation in northern Minnesota. Fish and macroinvertebrate community composition, habitat characteristics, and water chemistry parameters were examined to establish biological condition at four stream reaches and two wetland complexes. Fish assemblages were sampled in streams by electrofishing, and in wetlands with 24-hour trap net sets. Macroinvertebrates were collected qualitatively with D-frame kick nets, and quantitatively with Hess, Ekman, or Petite Ponar dredge sampling gear. Total number of fish and total lengths per species were determined within each stream reach to estimate catch per unit effort (CPUE). Macroinvertebrates were identified, enumerated, and the relative abundance and taxa richness per site determined. Stream habitat characteristics and water quality parameters at each site were summarized by point estimates along randomly placed transects. Invertebrate community composition between sites was predictable, with two wetland communities sharing similar characteristics (B5 and B7). The number of macroinvertebrate taxa was similar among stream sites (B1, B2, B3, and B6), but much higher than found in both wetland habitats. Three stream sites, including a designated reference reach located within the same drainage area (B1), provided similar community compositions. The remaining stream sampling location (B6) contained a macroinvertebrate and fish community that was unlike the previous three stream sites, and more similar to the wetland habitats based on the fish community composition. Fish communities among all sites were similar in respect to the functional proportions of taxa present. This survey suggests that the biological characteristics associated with stream and wetland sites sampled at the proposed NorthMet Mining Project site varied with respect to the distribution of fish and invertebrate functional categories between sites, but the overall community composition was typical of other systems in the region.
Sulfate and Mercury Chemistry of the St. Louis River in Northeastern Minnesota: A Report to the Minerals Coordinating Committee
(2009) Berndt, Michael; Bavin, Travis
This report presents technical data and information on water quality sampling from the St. Louis River related to sulfate and mercury contamination from mining that may affect human health. However the report contains raw data with little interpretation, and gives little guidance as to application of the findings to decision-making. The abstract and key findings are reproduced below. The St. Louis River and its major tributaries were sampled upstream from Cloquet during periods of high, medium, and low flow between September 2007 and October 2008. Special emphasis was placed on measuring sulfate (SO4) and mercury (Hg) distributions as well as other chemical parameters that might help to determine whether SO4 releases from the Iron Range have an impact on Hg speciation in the St. Louis River. These included, but were not limited to, dissolved organic carbon (DOC), dissolved iron (Fe), and the isotopic ratios for sulfur and oxygen atoms in dissolved SO4 (δ34SSO4 and δ18OSO4). Dissolved and particulate fractions of methyl mercury (MeHg), total mercury (THg), and bioavailable mercury (AHg) were additionally determined over a range of hydrologic conditions to identify primary source regions and transport mechanisms for Hg species. Results confirm that the majority of SO4 is derived from the iron mining district, and that SO4 added in the upstream portion of the St. Louis River is generally diluted downstream by waters from larger watersheds containing high percentages of wetlands. SO4, magnesium (Mg), calcium (Ca), sodium (Na), and chloride (Cl) concentrations all increase in the river, especially in the mining region, during periods of low-flow when groundwater inputs dominate chemistry of dissolved components. Variations in the relative concentrations of major elements and inδ34SSO4 and δ18OSO4 among the tributaries provide important clues to specific SO4 sources for each of the individual watersheds under varying flow conditions. Chemical data indicate that most SO4 from the mining region is derived from oxidation of small amounts of iron sulfide minerals present in stock piles, tailings, and pit walls containing Mg-rich carbonate minerals that are common in the Biwabik Iron Formation. Comparison with stream chemistry from 1955 to 1961 indicates SO4 sources were commonly present in the mining region before taconite mining became widespread in the region. Other chemical parameters in these data, particularly Ca and Mg, indicate the primary source for this SO4 was different from today. In contrast to SO4, Hg appears to be derived predominantly from wetlands, and is highest during periods of increased flow in the rivers. THg is well correlated to DOC concentration under most conditions, but quite variable during precipitation events when dissolved AHg and particulate SHg become more abundant in the rivers. MeHg concentrations in the St Louis River and its tributaries are also strongly correlated to DOC. Four sources of DOC are preliminarily inferred to be present in the river depending on the season and watershed characteristics, and it is believed that the relative amounts of DOC from each source may control the MeHg concentrations present in the river. These include: (1) DOC released from surface wetland areas containing low Fe (approximately 0.2 ng/mg Hg and 0.02 ng/mg MeHg in the DOC), (2) DOC containing almost no MeHg that is either produced in-stream or present in small amounts in natural groundwater, (3) DOC released from deep wetland areas following a major summer rain event containing very high MeHg and high Fe, and (4) DOC containing almost no MeHg in waters containing elevated dissolved Fe that seep slowly from deep within wetland areas under dry conditions. MeHg systematics appear to be very similar to those reported in two well-studied low-SO4 tributaries of the Rum River in east-central Minnesota. Additional sampling is planned to verify the above model and to more fully characterize mercury speciation during the warm summer months, particularly during periods when high Fe concentrations are present in the streams.

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