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Assessment of aquifer contamination near abandoned uranium mines in the North Cave Hills, South Dakota
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| Title | Assessment of aquifer contamination near abandoned uranium mines in the North Cave Hills, South Dakota |
| Subject | Mineral industries -- South Dakota
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| Date | 2011 |
| Identifier | NGWA%20Manuscript[1].pdf |
| Creator | Stetler, Larry D. ; Davis, Arden D. ; Stone, James J. |
| Relation-Is Part Of | South Dakota School of Mines & Technology. Web. |
| Digital Publisher | South Dakota School of Mines and Technology. Devereaux Library
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| Type | Text |
| Format | application/pdf |
| Language | eng |
| Rights | Copyright © 2011, South Dakota School of Mines and Technology. The original work may be protected by U. S. copyright law (Title 17, United States Code), which governs reproduction, distribution, public display, and other uses of protected works. Some uses may be legal with permission from the copyright holder if the use is fair use or within another legal exemption. The user of this work is responsible for compliance with the law. |
| Transcript | Assessment of Aquifer Contamination Near Abandoned Uranium Mines in the North Cave Hills, South Dakota Larry D. Stetler, Ph.D., CPG Department of Geology & Geological Engineering South Dakota School of Mines and Technology 501 E. St. Joeseph St. Rapid City, SD 57701. larry.stetler@sdsmt.edu Arden D. Davis, Ph.D., PE Department of Geology & Geological Engineering South Dakota School of Mines and Technology 501 E. St. Joeseph St. Rapid City, SD 57701 arden.davis@sdsmt.edu James J. Stone, Ph.D., PE Department of Civil and Environmental Engineering South Dakota School of Mines and Technology 501 E. St. Joeseph St. Rapid City, SD 57701 james.stone@sdsmt.edu Abstract An aquifer test of a water well located 1.9 miles NNE of the abandoned Riley Pass uranium mine in the North Cave Hills was conducted to assess potential for aquifer contamination from past mining activity. The well was drilled in 1979 and open hole completed in a 23 foot sand lens at a depth of 363 feet. The static water level was measured using a sonic water-level indicator at 250.6 feet below the top of the casing. The well was pumped for 60 minutes resulting in a drawdown of 16.6 feet followed by a 15 minute recovery period in which the water level rebounded to within 0.4 feet of the initial static level. Flow rates during pumping varied for the first 9 minutes increasing to 1.53 gal/min. for the duration of the test. Drawdown and recovery data were analyzed using the Theis method and AQTESLOV software. Transmissivity (T) calculated from both the drawdown and recovery data was 8 ft2/day. Hydraulic conductivity was determined to be 0.35 ft/day. Effective porosity and hydraulic gradient for the Hell Creek aquifer were determined to be ~0.06 and 0.008 (<1° to the NNE), respectively. The resulting ground-water velocity was determined to be ~0.047 ft/day. In the 53 years since the mines have been active, contamination having reached this aquifer would have been able to travel about 850, or <10 % of the distance from the mines to the well. This value does not include the additional time required for the contamination to travel vertically downward from the surface to the aquifer. The aquifer storage value of 0.0025 indicated aquifer confinement, restricting potential for downward contaminate migration through fractures in the overlying shale layers. Therefore, it appears unlikely that uranium mining in the North Cave Hills has affected groundwater wells in the regional aquifers. Introduction Uranium mining in northwestern South Dakota began in late 1954 within an approximately 3.5 km wide northwest trending strip crossing the central North Cave Hills (NCH). Mining was permitted under General Mining Laws and Public Law 357, which required no form of restoration. Most mines and mining prospects were located on United States Forest Service (USFS) administered land. Most of the uranium mines were located on relatively flat areas along the top of the numerous buttes that characterize the area. Mining consisted of removing overburden (up to 80 ft) to reach the ore zone which consisted of uranium-bearing lignite beds (Pipiringoes et al. 1965). Mining activity increased through the next decade but ceased in the NCH altogether in 1964. Total disturbed mined area in the NCH has been determined to be ~320 hectares (Fig. 1). Since that time, erosion has spread waste materials over ~400 hectares in the NCH alone. Additional deposition of material has occurred down-slope of the mine sites onto private land by gravity, water and wind transport. Site characterization studies of prospecting pits and contour benches have been performed on both USFS and private land (Pioneer Technical Services 2005) and on abandoned mine sites on USFS land (Pioneer Technical Services 2005; Portage 2005). Stetler and Stone (2008, in press), Stone et al. (2007) and Stetler and Stone (2007) have characterized off-site impacts from contamination due to surface and groundwater, slope failures, and wind transport onto surrounding private land. This paper addresses specifics of an aquifer test conducted to determine probability of groundwater contamination from historical mining activities. Geologic Setting The North Cave Hills rise about 400 feet above the surrounding plains to an altitude of approximately 3,400 feet. They are characterized by steep-sided and generally flat-topped, forested buttes rimmed by 60-150 feet high sandstone cliffs. Below the cliffs, steep, grass-covered slopes have formed from the softer sedimentary rocks including shale, siltstone, coal and loosely cemented sandstone. Regional bedrock consists of the Late Cretaceous Pierre Shale, Fox Hills sandstone, and the Hell Creek formations. Overlying Tertiary rocks include the Ludlow and Tongue River formations (Table 1). Both the Pierre and Fox Hills units outcrop further south, outside of the study area. The oldest rocks in the study area were Hell Creek formation clay, carbonaceous shale, siltstone, and quartz arenite sandstone units. The formation was exposed in small windows along drainages in the south and major drainages at the base of the North Cave Hills. The Cretaceous-Tertiary contact was gradational and poorly exposed and, thus, has been assigned to the lower-most coal unit in the overlying Tertiary (Ludlow) rocks. The lower-most Tertiary Ludlow formation consisted of gray to buff colored and relatively unconsolidated quartzose sandstone, siltstone, and clayey sand and silt units that have weathered to a yellowish gray. Occasional cross-bedding and ripple marks were evident in the sandy parts and ironstone concretions were ubiquitous throughout. Lignite coal and ligniferous shale units, referred to as ‘blackjack', were ubiquitous in the Ludlow. ND MT SD Figure 1. Location map of the North Cave Hills complex in NW South Dakota. Mined areas are designated by the pattern and alphabetic listing. Bluff B entails the Riley Pass mine area and was 1.9 miles south southwest of the tested well (black dot). The outline represents the USFS boundary. The Ludlow-Tongue River formation contact was sharp and marked by the appearance of the first massive sandstone outcrop. The lower-most sandstone, immediately above the Ludlow formation, was yellow to brown, cross-bedded quartz sand, slightly cemented with calcite, and massive having a thickness of 30-100 feet. The unit forms the principle aquifer in the area. The upper sandstone unit was massive, non-calcareous, loosely consolidated quartzose sand and ranged up to 135 feet thick. A uranium ore zone consisting of impure lignite beds intercalated in siltstone and claystone units occurred about 110-150 above the base of the formation. These coal units contained high uranium concentrations and were up to several feet thick. The uranium-bearing unit also separated the lower and upper sandstone units. Weathering and erosion of the above sequence has formed resistant sandstone rim rock capping the NCH (Fig. 2). Tertiary Tongue River formation rocks formed the rim rock and were underlain by shallow slopes comprised of loosely consolidated sand, silt, and clay layers with intercalated coal seams of the Tertiary Ludlow formation. Strata were relatively flat-lying with a regional dip of 1-2 degrees to the NE. Curtiss (1955) noted well-defined right-angle joint patterns which trended north-south and east-west, particularly conspicuous in the basal Tongue River massive indurated sandstone. These joints may have provided permeability pathways for the downward movement of uranium charged solutions into the Tongue River and Ludlow formations from the overlying White River sediments, considered to have been the uranium source rocks (Pipiringoes et al. 1965). It is also possible that these same joints, which were evident at the base of many abandoned uranium mines, could serve as conduits for entry of contaminants into underlying sandstone aquifers, affecting groundwater quality regionally. Table 1. General North Cave Hills stratigraphy and lithology (after Curtiss, 1955). Age Group Formation Thickness (ft.) Lithology Tongue 30 – 60 Yellow to brown, locally reddish to Early Fort River purple, soft, cavernous sandstone; Tertiary Union silt, clay, and coal (Paleocene) Ludlow ~250 Buff to yellow sand, sandstone, silt clay, and coal Hell ~425 Somber beds of drab, gray gumbo Creek sand, silt, coal, dinosaur bones Late Fox 20 – 75 Light gray to yellow, fine-grained Cretaceous Hills quartzose sand Pierre ~50 Dark gray bentonitic gumbo-like clay with concretions Figure 2. Bluffs in the North Cave Hills rise up to 400 feet above the surrounding plains and are comprised of the lower sandstone unit in the Tongue River formation. Groundwater Hydrology All human and stock watering needs in and around the NCH area are supplied by groundwater. Sources included springs, shallow unconfined aquifers, and deep confined aquifers. Aquifer depth varied from 30 to 55 feet for the unconfined alluvial systems to between 100 to 800 feet for the confined systems. Springs and shallow unconfined aquifer systems were classified as a local supply and the deep confined aquifers as a regional supply. Local supplies were derived from either precipitation infiltrating through the sandstone bluffs or precipitation filling small and isolated alluvial patches. These shallow alluvial aquifers occurred where isolated topographic lows were filled by alluvium above an impermeable shale. Three such systems were identified in the study area; two were isolated accumulations of aquifer material having limited lateral extent (additional wells drilled nearby failed to penetrate any alluvium) and the third occurred in shallow alluvium along an ephemeral channel, the extent of which was undetermined. Wells between 30 and 55 feet deep penetrated the shallow aquifers and were produced using a jet pump (depth to water <25 feet). Subsequently, springs developed in areas where downward infiltrating water encountered an impermeable layer, common along the many canyons that downcut through the bluffs. These type of springs were ubiquitous throughout the region and occurred on Forest Service and private land mostly near the base of the sandstone bluffs. Regional supplies were classified as water sources obtained from deep confined aquifers (>100 feet) that were recharged in zones removed from the NCH area. The majority of confined aquifers were sourced in various Cretaceous Fox Hills sandstone units. The Fox Hills has been described (Paterson and Kirchner, 1996; Pipiringoes et al., 1965; Page et al., 1956) as a 25-200 foot thick grayish-white to brown marine sandstone that constitutes the bulk of the regional drinking water supply. Overlying the Fox Hills, the Hell Creek formation consists of up to 425 feet of brown shale interbedded with discontinuous gray sandstone lenses and thin lignites in the upper half and mainly sandy beds in the lower half (Paterson and Kirchner, 1996). Some local wells may have been developed within the lower Hell Creek where the well depth was dependent upon local stratigraphy. Recharge zones for the Fox Hills units occurs 10's of kilometers to the west, south, and east. Some Hell Creek sandy units may recharge within close proximity to the NCH but were all confined at well locations. Local stratigraphic control below the surface to several thousand feet is mostly unknown. A general landowner survey was unsuccessfully conducted to obtain well information such as total depth, depth to water, producing formation, and production tubing size. Subsequently, a partial collection consisting of twelve photocopies of well completion reports was obtained from various sources and included two records from the SD Department of Environment and Natural Resources of location and depth data having no stratigraphic information, and six well records from the USGS National Water Information System (NWIS). Stratigraphic control was ultimately established using two cross sections constructed from published geologic maps (Page et al., 1956; Pipiringos et al., 1965) and well logs from 55 oil wells drilled throughout the region (Fig's. 2.4 and 2.5 in Stone et al., 2007). The resultant probable flow direction and gradient for the confined groundwater system in the Fox Hills formation was northeast at ~30 feet per mile, or ~0.3°. Although the slope was low, the results suggested water will flow in a northeasterly direction away from the Cave Hills toward the center of the Williston Basin. Previous Investigations and Sampling Strategy Results from previous studies in the NCH have been compiled in a compendium report (Pioneer Technical Services, 2005) that had a primary focus on USFS land, particularly the abandoned mines themselves and the immediate surrounding areas. Documentation included metals contamination in soil and surface waters as well as gamma radiation surveys (Pioneer Technical Services, 2002). These studies did not address groundwater concerns nor did they extend any appreciable distance off of USFS land. Data from the US Department of Energy's (US DOE) National Uranium Resources Evaluation (NURE) in the late 1970's included soil and groundwater sampling in all of Harding County. Results from the NURE are currently available online from the US Geological Survey (USGS). Several wells included in the current study were part of the NURE data. Current results were then compared to the NURE data to document any changes to water quality. A thorough groundwater quality study was recently completed (Stone et al., 2007) in the NCH that included 34 wells. Analytes were selected to allow comparison to previous studies and are shown in Table 2. Radionuclides were also analyzed in all water samples. Water wells sampled were selected to ensure representation of both human and stock water supplies and for evaluation of source, i.e., either local or regional. Results showed that gross alpha radiation was present in 26 of the 34 wells tested and occurred in a widely distributed pattern around the abandoned mine areas, both up- and down-gradient. Further, radionuclide contamination was present in wells from shallow depths in alluvial aquifers to deep confined aquifers several hundred feet deep. Three wells exceed the gross alpha MCL, the highest being 3x larger. Two of these occurrences were in shallow alluvial aquifers up-gradient from the Riley Pass mine complex and the other was down-gradient in a 400-foot deep confined aquifer source. Table 2. Analyte list for the groundwater study conducted in the North Cave Hills. Analyte Name Chemical Symbol Maximum Contaminant Level (MCL; mg/L) Arsenic As 0.01 Copper Cu 1.3 Molybdenum Mo - Selenium Se 0.05 Lead Pb 0.015 Thorium Th - Uranium U 0.03 Vanadium V - Radium Ra - Radium-226 Ra-226 5 pCi/L Uranium-235 U-235 - Gross Alpha - 15 pCi/L Data collected and analyzed during this groundwater study suggested that metals and radionuclides constitute naturally occurring components in the groundwater systems within the study area. Based on these results it was undetermined if the abandoned uranium mines in the NCH contributed to the metals content of the groundwater. Most likely the chemistry of surface water and local springs were affected by the presence of the mines but the deep aquifers should not have been impacted directly. Shale aquicludes present above the deep sources naturally protect infiltrating waters from reaching those aquifers, which were recharged away from the local area. The exception to this would be the presence of deep fracture systems allowing local infiltration to reach the water table, i.e., a leaky aquifer condition. Thus, initial groundwater quality results suggested additional aquifer testing to determine if such fractures exist in the area and determine the impact they might have on the deep groundwater system. Pumping Well Test and Analysis A pumping test was performed on November 9, 2007, at a deep well (Fig. 3) on privately-owned land located 0.75 miles east of the NCH and 1.9 miles NNE of the Riley Pass abandoned uranium mines (Fig. 1). Groundwater quality sampling results showed this well to contain a gross alpha value of 8 pCi/L, one-half the MCL. The well owner reported that the water level was about 250 ft below the surface, and the total depth was about 360 ft which was later confirmed from well logs acquired for this well. From stratigraphic sections, well logs and local geology, the well was most likely completed in the upper Hell Creek aquifer. At this depth, the aquifer was confined having almost the entire thickness of overlying Ludlow shale units serving as aquicludes layers. Figure 3. Well test setup on a 360 foot deep well in the North Cave Hills. A sonic water-level indicator was mounted on a riser pipe that accessed the casing ID. A sonic water-level indicator was used to measure the static water level and drawdown during the test. The static water level was 250.6 ft below the top of a temporary riser pipe set up for measuring water levels during the aquifer test. When the pump was started, water-level measurements were collected for 60 minutes (Table 3). The pumping rate was approximately 1.53 gal/min during most of the test. After the pump was shut off, recovery measurements were collected for an additional 15 minutes (Table 4). Water-level measurements during pumping and recovery are shown graphically on figure 4. Recovery values were determined from figure 4, by extension of the drawdown curve. In Table 4, t refers to the time since the pump started, and t' refers to the time since the pump stopped. Drawdown and recovery data were analyzed with the Theis equation (Freeze and Cherry, 1979) and methods outlined by Driscoll (1986). AQTESOLV® software was used for analysis. During pumping, early drawdown values were influenced by storage of water in the well casing (Fig. 5). The Theis method (Fig. 5) showed a transmissivity (T) of approximately 8 ft2/day and a storage coefficient of 0.0025. Residual-drawdown analysis of recovery data (Fig. 6) also showed a transmissivity of about 8 ft2/day. Table 3. Drawdown vs. time data from pumping test in the North Cave Hills. Time Drawdown Depth to (min) (ft) water (ft) Static Level 250.6 Pump on 0.167 1.0 251.6 0.333 1.8 252.4 0.5 1.5 252.1 0.667 1.9 252.5 0.833 2.2 252.8 1 2.4 253.0 2 5.2 255.8 3 6.5 257.1 4 7.9 258.5 5 8.5 259.1 6 9.3 259.9 7 9.5 260.1 8 10.0 260.6 9 10.3 260.9 10 10.4 261.0 12 11.7 262.3 15 12.4 263.0 20 13.8 264.4 25 14.2 264.8 30 14.7 265.3 40 15.3 265.9 50 15.9 266.5 60 16.6 267.2 Hydraulic conductivity (K) was determined using: K = T/b (1) where b = saturated thickness Local well logs were utilized to determine that saturated thickness for the water-bearing part of the Hell Creek aquifer was about 25 ft. However, this value was assigned a range from 20 ft to 30 ft to account for local variability that could occur in aquifer properties. Hydraulic conductivity, therefore, could range from about 0.27 ft/day to 0.4 ft/day. Figure 4. Depth to water vs. time during pumping test and recovery. 0.1 1. 10. 100. 1. 10. 100. Time (min) Displacement (ft) Obs. Wells Old Well Aquifer Model Confined Solution Theis Parameters T = 8.043 ft2/day S = 0.002461 Kz/Kr = 1. b = 25. ft Figure 5. Theis analysis of drawdown vs. time data from pumping test well. Note effects of storage of water in well casing during first ten minutes of test. Table 4. Recovery data vs. time data from pumping test in the North Cave Hills. Time Recovery Residual t/t' Depth to (min) (ft) drawdown water (ft) Pump off 60.167 3.3 13.3 361 263.9 60.333 4.42 12.2 181 262.8 60.5 5.23 11.4 121 262.0 60.667 5.44 11.2 91 261.8 60.833 5.85 10.8 73 261.4 61 6.56 10.1 61 260.7 61.5 7.27 9.4 41 260.0 62 7.98 8.7 31 259.3 63 10.19 6.5 21 257.1 64 11.7 5.0 16 255.6 65 12.92 3.8 13 254.4 66 14.08 2.7 11 253.3 67 14.5 2.3 9.57 252.9 68 14.82 2.0 8.5 252.6 69 15.04 1.8 7.67 252.4 70 15.22 1.7 7 252.3 72 15.4 1.6 6 252.2 75 15.7 1.4 5 252.0 1. 10. 100. 1000. 0. 4. 8. 12. 16. 20. Time, t/t' Residual Drawdown (ft) Obs. Wells Old Well Aquifer Model Confined Solution Theis (Recovery) Parameters T = 8.014 ft2/day S/S' = 2.592 Figure 6. Residual-drawdown analysis of data from pumping test well. Ground-water velocity (v) was calculated using: v = (K/ ) ( h/ s) (2) where h/ s = hydraulic gradient = effective porosity Hydraulic gradient was assumed to be 0.008, based on the regional dip of rocks and limited water-level data in surrounding wells, but it could vary from about 0.005 to 0.01 in this area. Effective porosity of the Hell Creek aquifer has been estimated to be 0.06 by Rahn (1985), but it could reasonably vary from about 0.05 to 0.1. On the basis of this information, the calculated ground-water velocity could vary from about 0.014 ft/day to about 0.08 ft/day (5 to 29 ft/yr). Discussion and Conclusions The pumped well was 1.9 miles (10,000 ft) north northeast of the abandoned Riley Pass uranium mines, slightly more northward than the calculated groundwater gradient. These mines were active beginning in 1954, thus, 53 years has passed since initial mining activity and the analysis of the pumping well data. Assuming that the calculated ground-water velocity represents flow conditions in the Hell Creek aquifer, groundwater and dissolved contaminants could have moved between 270 and 1550 ft in the ensuing 53 years, depending on aquifer properties and accounting for local variations in conditions. This value represents <3% to about 15% of the distance between the mines and the well. This estimate does not include the time necessary for contaminants to move downward from the land surface to the aquifer. Table 1 shows that radionuclides sourced from uraniferous lignites comprising the ore zone in the Tongue River would have been required to migrate vertically downward through the Ludlow formation to reach the sandy aquifer lenses in the Tongue River. Assuming fracture flows one order-of-magnitude greater than calculated ground-water velocity, downward migration would have required between 7.1 years (for the lowest velocity) and 1.25 years (for the highest velocity). In either situation, contamination sourced from the mines would not have reached the location of the pumped well and travel distances would be reduced from those given above. However, these analyses indicate the Hell Creek aquifer is confined because water levels in wells completed in the aquifer are above the top of the sandy, water-bearing layers (110 ft in the test well), and because the storage coefficient of 0.0025 is in the range that is typical of a confined aquifer. There are no data suggesting downward migration has or is occurring. Thus, it appears likely that the gross alpha measurement of 8 pCi/L in test well is naturally occurring rather than the result of uranium mining in the North Cave Hills. References Curtiss, Robert, E., 1955, A Preliminary Report on the Uranium in South Dakota, South Dakota Geological Survey, Report of Investigations No. 79, 102 pages. Driscoll, F.G., 1986, Groundwater and wells, 2nd ed.: Johnson Division, 1089 p. Freeze, R.A., and Cherry, J.A., 1979, Groundwater: Prentice-Hall, Englewood Cliffs, New Jersey, 604 p. http://jurassic2.sdgs.usd.edu/pubs/pdf/RI-079.pdf. Page, L.R., H.E. Stocking, and H.B. Smith, 1956, Contributions to the geology of uranium and thorium by the United States Geological Survey and Atomic Energy Commission for the United Nations international conference on the peaceful uses of atomic energy, Geneva, 1955. Paterson, C.J. and J.G. Kirchner, 1996, Guidebook to the geology of the Black Hills, South Dakota, SDSM&T Bulletin 19, p230. Pioneer Technical Services, 2002, Final Site Investigation Report for the Riley Pass Uranium Mines, Harding County, South Dakota. Pioneer Technical Services, 2005, Draft final engineering/cost analysis (EE/CA) for the Riley Pass Uranium Mines, Harding County, South Dakota, http://www.fs.fed.us/r1/custer/projects/Planning/nepa/Riley_Pass/index.shtml Pipiringos, G.N., W.A. Chisholm, and R.C. Kepferle, 1965, Geology and uranium deposits in the Cave Hills area, Harding County, South Dakota, USGS Prof. Pap. 476-A, US Gov Printing Office, 64p, 4 plates. Portage, 2005, Final human health and ecological risk assessment for the Riley Pass Uranium Mines in Harding County, South Dakota, http://www.fs.fed.us/r1/custer/projects/Planning/nepa/Riley_Pass/EECA/Appendix%20 D.pdf Rahn, P.H., 1985, Ground water stored in the rocks of western South Dakota, in Rich, F.J., ed., Geology of the Black Hills, South Dakota and Wyoming, 2nd ed.: American Geological Institute, Alexandria, Virginia, p. 154-173. Stetler, L.D. and Stone, J.J., 2007, Off-site impacts from abandoned uranium mines in the North Cave Hills, Harding County, South Dakota, Proceedings South Dakota Academy of Science, 86:159-167. Stetler, L.D. and Stone, J.J., 2008, Human health impacts from surface dust near abandoned uranium mines in Harding Co., South Dakota, Proceedings South Dakota Academy of Science, 87: in press. Stone, J.J., L.D. Stetler, and A. Schwalm, 2007, Final report: North Cave Hills abandoned uranium mines impact investigation, SDSM&T (http://uranium.sdsmt.edu), 202 pg., App A-F. Biographical Sketches Larry D Stetler is associate professor of geological engineering at the South Dakota School of Mines and Technology in Rapid City, SD. He received his PhD from Washington State University. His current funded research topics include 1) abandoned mine impact studies in western South Dakota, 2) landuse development and slope stability studies in Pennington County, 3) identification of sources and deposition of mercury in SD, 4) instrumentation and monitoring of groundwater reduction at Homestake DUSEL including installation of a microclimate network in the mine, 5) installation and monitoring of a tiltmeter network at DUSEL to monitor ground deflection from dewatering and construction activities, and 6) establishing erosion rates at Badlands National Park and development of a fossil resource management model. He is a member of the Association of Engineering and Environmental Geologist (AEG), the American Institute of Professional Geologists (AIPG), and South Dakota Academy of Science (SDAS). He is currently the Vice President and President-elect of the AIPG SD Chapter and serves as a co-editor of the Proceedings of the South Dakota Academy of Science. Arden D. Davis is a Professor in the Department of Geology and Geological Engineering at South Dakota School of Mines and Technology. He received his B.A. degree in Geology from the University of Minnesota, and his M.S. and Ph.D. degrees in Geological Engineering from South Dakota School of Mines and Technology. He is a registered professional engineer in South Dakota. His research interests include ground-water resources, water quality, and abandoned mines. James J. Stone received his PhD and post doctorial studies in Environmental Engineering from Penn State University. He has 5 years of environmental consulting experience and is a registered professional engineer in Colorado. His current research focus is contaminant fate and transport within environmental systems. |
| CONTENTdm number | 12451 |
| CONTENTdm file name | 12452.pdf |
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