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Characterization of the upper aquifer beneath Smelterville Flats with implications for mitigation of groundwater contamination Item Info

In the early part of this century, the Smelterville Flats area near Kellogg, Idaho received mining, milling, and metallurgical wastes. Mine wastes were deposited on the flood plain or in the channel of the South Fork of the Coeur d'Alene River. In the early 1900s, a series of dams were built across the South Fork of the Coeur d'Alene River at the western end of Smelterville Flats in an attempt to control the downstream transport of mine wastes. Mine wastes and other sediments were deposited behind this dam. The site, known as Smelterville Flats, is the largest uncontrolled deposit of mining wastes that remains in the South Fork of the Coeur d'Alene River Valley. Water levels and water quality samples were collected from existing monitoring wells within the Smelterville Flats study area. A more intensive study was conducted on a small sub-area of the Smelterville Flats study area known as the Bureau of Land Management (BLM) sub-area. Ten sets of piezometers were installed to monitor water quality and water levels in the upper aquifer beneath Smelterville Flats in the BLM sub-area. A pumping well and observation wells were installed in the BLM sub-area in order to conduct a pumping test in the upper aquifer to determine aquifer coefficients. Ground water level gradients in the study area indicate that the ground water flow direction is from east to west, following the general gradient of the valley of the South Fork of the Coeur d'Alene River. Water levels also indicate that the South Fork of the Coeur d'Alene River is a losing stream in the east end of the study area and a gaining stream in the west end of the study area. Shallower monitoring wells in the upper aquifer within the BLM sub-area consistently had higher concentration of ions associated with mining wastes than deeper monitoring wells installed in the same aquifer at the same location. Oxidation of the mine wastes may occur in the unsaturated zone in the presence of oxygen, or in the presence of oxygen and water if the film of water is thin enough to allow the diffusion of oxygen to the reaction sites. The thin layer of water surrounding the wastes may become a concentrated solution of soluble reaction products. Infiltration of precipitation, and rises in ground water levels flush and transport the soluble reaction products from the reaction sites on the wastes into the shallow ground water system. The oxidation products are removed from the reaction sites, thereby producing fresh reaction sites for the next influx of oxygen. The reaction products may then be transported by the ground water flow system, which ultimately discharges to the South Fork of the Coeur d'Alene River at the western end of Smelterville Flats. Based on the data collected, potential mitigative measures were evaluated and analyzed in order to minimize the adverse long-term effects of mine waste on the ground water and surface water systems. Potential mitigative measures that are evaluated include treatment of the shallow aquifer water, elimination or reduction of ground water flow through the shallow aquifer, removal of the major sources of metal ions, and no action. The continuation of research to identify or develop a mechanism to extract marketable metals from the wastes on Smelterville Flats appears to constitute the most appropriate course of action.

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Title:
Characterization of the upper aquifer beneath Smelterville Flats with implications for mitigation of groundwater contamination
Authors:
Kunkel, Douglas
Date Created (ISO Standard):
1993-11
Description:
In the early part of this century, the Smelterville Flats area near Kellogg, Idaho received mining, milling, and metallurgical wastes. Mine wastes were deposited on the flood plain or in the channel of the South Fork of the Coeur d'Alene River. In the early 1900s, a series of dams were built across the South Fork of the Coeur d'Alene River at the western end of Smelterville Flats in an attempt to control the downstream transport of mine wastes. Mine wastes and other sediments were deposited behind this dam. The site, known as Smelterville Flats, is the largest uncontrolled deposit of mining wastes that remains in the South Fork of the Coeur d'Alene River Valley. Water levels and water quality samples were collected from existing monitoring wells within the Smelterville Flats study area. A more intensive study was conducted on a small sub-area of the Smelterville Flats study area known as the Bureau of Land Management (BLM) sub-area. Ten sets of piezometers were installed to monitor water quality and water levels in the upper aquifer beneath Smelterville Flats in the BLM sub-area. A pumping well and observation wells were installed in the BLM sub-area in order to conduct a pumping test in the upper aquifer to determine aquifer coefficients. Ground water level gradients in the study area indicate that the ground water flow direction is from east to west, following the general gradient of the valley of the South Fork of the Coeur d'Alene River. Water levels also indicate that the South Fork of the Coeur d'Alene River is a losing stream in the east end of the study area and a gaining stream in the west end of the study area. Shallower monitoring wells in the upper aquifer within the BLM sub-area consistently had higher concentration of ions associated with mining wastes than deeper monitoring wells installed in the same aquifer at the same location. Oxidation of the mine wastes may occur in the unsaturated zone in the presence of oxygen, or in the presence of oxygen and water if the film of water is thin enough to allow the diffusion of oxygen to the reaction sites. The thin layer of water surrounding the wastes may become a concentrated solution of soluble reaction products. Infiltration of precipitation, and rises in ground water levels flush and transport the soluble reaction products from the reaction sites on the wastes into the shallow ground water system. The oxidation products are removed from the reaction sites, thereby producing fresh reaction sites for the next influx of oxygen. The reaction products may then be transported by the ground water flow system, which ultimately discharges to the South Fork of the Coeur d'Alene River at the western end of Smelterville Flats. Based on the data collected, potential mitigative measures were evaluated and analyzed in order to minimize the adverse long-term effects of mine waste on the ground water and surface water systems. Potential mitigative measures that are evaluated include treatment of the shallow aquifer water, elimination or reduction of ground water flow through the shallow aquifer, removal of the major sources of metal ions, and no action. The continuation of research to identify or develop a mechanism to extract marketable metals from the wastes on Smelterville Flats appears to constitute the most appropriate course of action.
Subjects:
mine wastes water quality groundwater pollution
Location:
Coeur d'Alene Basin
Latitude:
47.52
Longitude:
-116.56
Collection:
Coeur d'Alene Basin
Rights:
Rights to the digital resource are held by the University of Idaho. http://www.uidaho.edu/
Publisher:
University of Idaho
Contributing Institution:
University of Idaho
Type:
Text
Format:
application/pdf
Cataloger:
wbv
Date Digitized:
2012

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Source
Preferred Citation:
"Characterization of the upper aquifer beneath Smelterville Flats with implications for mitigation of groundwater contamination", Idaho Waters Digital Library, University of Idaho Library Digital Collections, https://www.lib.uidaho.edu/digital/iwdl/items/iwdl-cda_kunkel_1993.html
Rights
Rights:
Rights to the digital resource are held by the University of Idaho. http://www.uidaho.edu/
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