USGS Washington Water Science Center
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WA413 - Long-Term Monitoring of the Quality of Groundwater at the Midnite Mine, Stevens County, Washington - Completed FY1998
Introduction - Midnite Mine is an inactive uranium mine, located approximately 50 miles northwest of Spokane, Washington, within the Spokane Indian Reservation. The Midnite Mine drainage basin consists of approximately 1.5 square miles within the Blue Creek Drainage Basin and encompasses the minesite. Between 1988 and 1995, the U.S. Bureau of Mines (USBM) operated a ground-water quality monitoring network at the minesite, during which time a deterioration of the water quality was observed in a number of wells. During September and October 1996, the U.S. Geological Survey (USGS) evaluated the operational condition of the USBM wells at the minesite and collected 19 environmental samples to characterize the current quality of the ground water.
Problem - At the present time, the quality of the ground water at Midnite Mine is not being monitored. Thus, it is not possible for the Spokane Indian Tribe, the Bureau of Indian Affairs, or the Bureau of Land Management to assess the status of or to monitor the effects remediation activities may have on the quality of ground water in the Midnite Mine drainage basin.
Objectives - The principal objective of this study is to characterize and monitor the quality of ground water within the Midnite Mine drainage basin. Secondary objectives include: 1) determining the magnitude of seasonal variation in the quality of ground water; 2) characterizing the effects to the quality of ground water from large storm events; and 3) ascertaining changes to the quality of ground water as a result of remediation activities.
Approach - Water-quality samples will be collected from all operational wells at the minesite, once during the early fall months (September or October) of each year. Concentrations of various dissolved common constituents, trace elements, and radionuclides will be determined for all samples collected. As many as nine wells will be sampled and measured at three other times during the year to document seasonal fluctuations in both ground-water quality and elevation. Samples will also be collected from two wells at three times after a storm event that results in considerable infiltration of rainwater, and most likely snowmelt, to characterize effects to the quality of ground water from large storm events.
WA355 - Ground-water Resources of Selected Areas on the Spokane and Kalispel Indian Reservations, Northeastern Washington - Completed FY1998
Problem - The Spokane and Kalispel Indian Reservations are located in northeastern Washington. The primary use of ground water on both reservations is for domestic purposes. Ground water on the Spokane Reservation is obtained from glacial deposits of silt and sand and from the underlying basalt. Some wells go dry in late summer and there is concern that cattle feedlot operations and septic tanks may be adversely affecting water quality. Most domestic wells on the Kalispel Reservation are located on the flood plain of the Pend Oreille River which is composed primarily of silt. These wells yield only small quantities of water. Concentrations of arsenic, cadmium, and iron are often elevated; at times, the concentration of dissolved arsenic has exceeded drinking water standards. A few wells have been drilled in narrow gravel terraces overlooking the flood plain. These are reported to yield water in sufficient quantity and quality for use as domestic supplies. The Bureau of Indian Affairs has identified two areas within the Spokane Reservation, and the terraced areas of the Kalispel Reservations, as locations where future ground-water development may occur. A better understanding of the extent and hydraulic characteristics of the aquifers in these two areas is needed.
Objectives - The objectives of the study are to (1) determine the areal extent, lithology, and thickness of unconsolidated surficial materials and of the underlying basalt on the Spokane Reservation and of the Pleistocene fluvial and terrace deposits on the Kalispel Reservation; (2) attempt to delineate the water-level surface of individual aquifers on the Spokane Reservation and describe the magnitude of seasonal water-level changes beneath both reservations; (3) define the regional patterns of water quality in the study areas and determine if any areas of poor ground-water quality exist; (4) estimate the hydraulic characteristics of the principal aquifers; and (5) estimate average annual recharge for aquifers in the study areas.
Approach - About 100 to 150 wells will be inventoried and the data entered into NWIS. Drillers' logs and available geologic maps will be used to define the geometry of the unconsolidated basalt aquifers and water-level data will be plotted on maps of individual aquifers and used to delineate piezometric heads. Water-quality samples will be collected to define the regional patterns of water quality and determine if any areas of poor ground-water quality exist. Transmissivity and hydraulic conductivity for wells will be estimated and plotted for each aquifer. Average annual recharge will be estimated using regression equations developed for the Columbia Plateau RASA project. All data collected will be entered into a GIS database (ARC/INFO) and provided to the Bureau of Indian Affairs.
WA003-36 - The Quality of Ground Water at the Midnite Mine, Stevens County, Washington - Completed FY1996
Background - Midnite Mine is an inactive uranium mine, located approximately 50 miles northwest of Spokane, Washington, and lies within the Spokane Indian Reservation (fig.1). Activity at the mine ceased in 1982, and since then ground and surface waters have accumulated on-site in a retention pond at the downgradient boundary of the mine and in two pits (3 and 4; fig. 2). Furthermore, water accumulating in the retention pond has been pumped back into pit 3. The initial stage of reclamation has begun as water from pit 3 is being treated on-site to remove radium, uranium, various trace elements, and suspended sediments and is then discharged into the east mine drainage. Subsequent plans to reclaim the site may include sequestering pyrite-rich waste rock and low-grade ore, still stockpiled at the minesite, in one of the pits, followed by capping the pit with impermeable material; installing drains to capture surface runoff and route it to the water-treatment plant; and regrading and revegetating the minesite to maximize evapotranspiration and to reduce erosion and infiltration.
Problem - At present, the quality of the ground water at the minesite is not being monitored. Thus, it is not possible to assess the status of the ground-water quality nor the effects of the reclamation activities at the minesite; Furthermore, it is difficult to predict what effects reclamation activities may have on the long-term quality of the ground and surface waters at the minesite or in the basins adjacent to or near Midnite Mine.
Objectives - The primary objective of this study is to characterize and monitor the quality of ground water at Midnite Mine. A secondary objective is to determine the magnitude of seasonal variation in the ground-water quality at the minesite.
Approach - Water-quality samples will be collected from 8 of the 27 wells located within the minesite, during as many as 8 sampling periods. At least 3 sampling periods will follow large rainfall or snowmelt events at the minesite. Samples will be collected from the same wells during all sampling periods.
The pH, conductivity, alkalinity, and temperature will be determined for all samples collected. The concentrations of selected dissolved common constituents (table 1) in the water samples will be determined using standard methods (Fishman and Friedman, 1989), the activities of selected dissolved radionuclides (table 1) will be determined by gamma spectroscopy (Timme, 1994), and the activities of radon-222 will be determined using a liquid scintillation process (Pritchard and others, 1980). All filtering and preservation required for each analyses will follow the procedures outlined by Horowitz and others (1994) and by Wood (1981), and all laboratory analyses will be performed by the U. S. Geological Survey National Water Quality Laboratory (NWQL) in Arvada, Colorado. Quality-assurance samples, which will consist of duplicate environmental samples and field blank samples, will also be submitted to the NWQL for analysis.
WA003 - Discharge and Water-Quality Data from Seeps, Springs, and Streams near Midnite Mine, Stevens County, Washington - Completed FY1995
Background - Uranium mining activity at the Midnite Mine, located about 50 miles northwest of Spokane, Washington, ceased in 1982. Since that time, ground and surface waters have accumulated on-site in a retention pond at the downgradient boundary of the mine and in two unused pits. Also, ground water discharging by way of seeps in and around the mine, and water accumulating in the retention pond, have been pumped back into one of the unused pits (pit 3). The initial stage of reclamation has begun as water from pit 3 is being treated on-site to remove radium, uranium, trace elements, and suspended sediment and then released to the environment. Subsequent reclamation plans include sequestering pyrite-rich waste rock and low-grade ore, still stockpiled on-site, in one of the pits (pit 4), and capping the filled-in pit with impermeable material; installing drains to capture surface runoff, and routing it to the water-treatment plant; and regrading and revegetating the mine area to maximize evapotranspiration and to reduce erosion and infiltration.
Problem - At the present time, there are no data for the quantity or quality of ground water in the Midnite Mine basin that predates mining activity. Thus, it is not possible for the U.S. Bureau of Mines (USBOM) to assess the effectiveness of reclamation activities or to guide efforts to return the mine site to pre-mining conditions.
Objectives - The principal objective of this study is to collect data from nearby basins with topographic, climatic, and geologic characteristics as close to those of the Midnite Mine as possible so that pre-mining hydrologic conditions can be inferred and reclamation activities in the Midnite Mine basin can be evaluated. A secondary objective is to determine the magnitude of seasonal variations in water quantity and quality in the basins studied.
Approach - A reconnaissance-level assessment of seeps, springs, and streams in parts of the Sand Creek and Blue Creek basins (fig. 1) will provide data which can be compared to data from the Midnite Mine basin. Data will be collected during two sampling trips to the area which will coincide with periods of high and low ground-water levels. The first sampling trip will begin in late summer, 1994, following an initial field reconnaissance to locate likely sites for subsequent sampling. The sites will be located on aerial photographs and topographic maps for future reference and determination of latitude, longitude, and elevation. Sites inventoried for possible sampling will include seeps, springs, and streams of significant size but not shown on existing topographic maps. Drainages with established stream channels but without flow at the time of the first field trip will be noted; these sites will be revisited during the second sampling trip. Vegetation conditions at each of the sites selected for measurement/sampling will be recorded. Selected sites will include points on Blue Creek and Sand Creek both above and below the study area.
The first sampling will begin in August, 1994, immediately following the reconnaissance trip. Where possible, discharge measurements will be made at sampling sites, prior to sampling. It may be possible to measure discharge with a Price pygmy current meter, but a portable weir and(or) flume may be required. Field measurements will be made of water temperature, specific conductance, pH, alkalinity, and dissolved-oxygen concentration. Water samples will be collected for the following laboratory analyses which include constituents required by the National Pollutant Discharge Elimination System (NPDES) permit for the water-treatment plant, and Nuclear Regulation Commission (NRC) regulations for mine effluent.
WA296 - An Investigation of Hydrologic Conditions at the Midnite Mine and Vicinity Stevens County - Completed FY1989
Problem - Midnite Mine is an open-pit uranium mine near Spokane. Mining activity ceased in early 1982. Since that time, water has accumulated in the ore pits and now threatens to overflow from pit 4, near the north end of the mine. The quality of the water in the pit is presently unknown, and it is uncertain whether and when the pit will actually overflow. In 1980, seeps issuing from the bases of waste piles near the down-gradient end of the mine were shown to contain radium, uranium, and ammonia in potentially harmful concentrations, as well as low-pH water. All water from Midnite Mine discharges to Blue Creek, tributary of FDR Lake, and Bureau of Indian Affairs (BIA) and Bureau of Land Management (BLM) are concerned about the hazards posed by the mine drainage.
Objectives - Determine a monthly and annual water budget for the study area. Describe the quality of precipitation falling on the mine during the study period with respect to pH. Describe the quality of ground-water draining from the alluvium in the study area into Blue Creek. Describe the quality of surface water at selected points in time for major pits and ponds, drainage into Blue Creek and Blue Creek. Determine mean daily values of discharge and water temperature, specific conductance and pH. Design a water-quality monitoring program that will allow the determination of the annual loads of selected chemical constituents discharged from the mine into Blue Creek. Recommend the best types of tracing agents and procedures to examine ground-water flow paths in the lower part of the mine.
Approach - Monthly and annual water budgets will be calculated based on precipitation, evaporation, surface-water outflow and ground-water outflow. The pH of precipitation will be monitored by collection precipitation in a wet-dry sampler and measuring pH weekly on the composite sample. The quality of ground-water draining the alluvium will be determined by collecting a sample on a monthly basis from a well at or near site 32 and analyzing it for water temperature, pH, specific conductance and a suite of 38 water-chemistry constituents. The quality of surface water bodies in the study area will be described by sampling the major pits and ponds within the mine twice yearly and selected streams once per month. Continuous water-quality monitors will be used to measure and record water temperature, pH and specific conductance at selected stream sites.
WA288 - Landslide Potential Near Sherwood Uranium Mine, Spokane Indian Reservation - Completed FY1983
Problem - The Sherwood Uranium Mine is situated on a ridge overlooking the Spokane River Arm of FDR Lake, which is used for irrigation, recreation, and domestic drinking water. The glacial deposits underlying the mine spoils area could be unstable and susceptible to sliding. Landslide or surface water runoff containing radionuclides and toxic metals could enter the Lake. Runoff also relates to erosion, mudflows, slope stability, and landsliding. A complete understanding of surface-water drainage is essential for proper supervision of mining activities.
Approach - Information on terrace scarp slope, height, submergence beneath FDR Lake, and lithology will be gathered in the field, from aerial photographs, and detailed topographic maps. Seismic refraction surveys will determine configuration of bedrock, location of water table, and amount of glacial deposit. Auger test holes will confirm seismic data. Piezometers will be installed and monitored to determine timing, amount, and chemistry of recharge water. Surface-water drainage patterns will be determined and runoff samples analyzed for field parameters, common ions, trace metals, and radionuclides. A simple mathematical model will be constructed for assessing landslide potential.