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Characterization of ground-water flow between the Canisteo Mine Pit and surrounding aquifers, Mesabi Iron Range, Minnesota

Water-Resources Investigations Report 2002-4198

Prepared in cooperation with the Minnesota Department of Natural Resources
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Abstract

The U.S. Geological Survey, in cooperation with the Minnesota Department of Natural Resources, conducted a study to characterize ground-water flow conditions between the Canisteo Mine Pit, Bovey, Minnesota, and surrounding aquifers following mine abandonment. The objective of the study was to estimate the amount of steady-state, ground-water flow between the Canisteo Mine Pit and surrounding aquifers at pit water-level altitudes below the level at which surface-water discharge from the pit may occur. Single-well hydraulic tests and stream-hydrograph analyses were conducted to estimate horizontal hydraulic conductivities and ground-water recharge rates, respectively, for glacial aquifers surrounding the mine pit. Average hydraulic conductivity values ranged from 0.05 to 5.0 ft/day for sands and clays and from 0.01 to 121 ft/day for coarse sands, gravels, and boulders. The 15-year averages for the estimated annual recharge using the winter records and the entire years of record for defining baseflow recession rates were 7.07 and 7.58 in., respectively. These recharge estimates accounted for 25 and 27 percent, respectively, of the average annual precipitation for the 1968-82 streamflow monitoring period. Ground-water flow rates into and out of the mine pit were estimated using a calibrated steady-state, ground-water flow model simulating an area of approximately 75 mi2 surrounding the mine pit. The model residuals, or difference between simulated and measured water levels, for 15 monitoring wells adjacent to the mine pit varied between +28.65 and –3.78 ft. The best-match simulated water levels were within 4 ft of measured water levels for 9 of the 15 wells, and within 2 ft for 4 of the wells. The simulated net ground-water flow into the Canisteo Mine Pit was +1.34 ft3/s, and the net ground-water flow calculated from pit water levels measured between July 5, 1999 and February 25, 2001 was +5.4 ft3/s. Simulated water levels and ground-water flow to and from the mine pit for the calibrated steady-state simulation were most sensitive to changes in horizontal hydraulic conductivity, suggesting that this characteristic is the predominant parameter controlling steady-state water-level and flow conditions. A series of 14 steady-state simulations at constant pit water-level altitudes between 1,300 and 1,324 ft was completed with the calibrated model to assess the effect of current and potential future pit water-level altitudes on ground-water inflow to and outflow from the mine pit. Total simulated ground-water inflow to the mine pit at a constant pit water-level altitude of 1,300 ft was 1.40 ft3/s, with a total simulated ground-water outflow of 0.06 ft3/s discharging from the mine pit to local aquifers. Steady-state simulations indicate that total simulated ground-water inflow will decrease from 1.40 to 1.00 ft3/s and total simulated ground-water outflow will increase from 0.06 to 0.91 ft3/s as the pit water-level altitude rises from 1,300 to 1,324 ft. When the pit water-level altitude is 1,324 ft3/s, the lowest pit-rim altitude, the simulated net ground-water inflow is 0.09 ft3/s. At pit water-level altitudes between 1,302 and 1,306 ft, all but a small rate (less than 0.01 ft3/s) of the total simulated ground-water outflow from the pit occurs in the Trout Lake area. At pit water-level altitudes between 1,308 and 1,324 ft, simulated outflow occurs in three outflow locations: the Trout Lake, the Prairie River, and Holman Lake areas.

Study Area

Additional publication details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Characterization of ground-water flow between the Canisteo Mine Pit and surrounding aquifers, Mesabi Iron Range, Minnesota
Series title:
Water-Resources Investigations Report
Series number:
2002-4198
Year Published:
2002
Language:
English
Publisher:
U.S. Geological Survey
Publisher location:
Mounds View, MN
Contributing office(s):
Minnesota Water Science Center
Description:
iv, 30 p.
Country:
United States
State:
Minnesota
Other Geospatial:
Canisteo Mine Pit
Online Only (Y/N):
N
Additional Online Files (Y/N):
N