In order to analyze the effectiveness of the above plan for mitigating lake
impacts, the DNR/USGS
lake model was used. The model simulated lake level declines caused by the
groundwater drawdown.
When minimum lake levels were reached, the model added water to the lakes
at a rate equal to the
mine-induced seepage. The modeling showed that lake levels would continue
to decline even with
mitigation. This is because the proposed mitigation rate, which is equal
to the mine-induced seepage
rate at minimum lake levels, is less than the average increase in lake seepage
caused by the mine
(Table 3-20). As a result, the mitigation pumping would not provide adequate
quantities of water to
the lakes to prevent adverse impacts. Little Sand Lake would be below minimum
levels 82-85% of
the time even with mitigation. Deep Hole Lake would fall below the minimum
level about twice as
frequently under the mitigation plan as it normally would. Average lake levels
would be reduced by
up to 1 foot.

                                           Table 3-20
                  Hydrologic Impacts to Lakes From the Proposed Mitigation
Plan

                    Average      Average Increase        % Time
                    Mitigation       in Lake            Below Minimum   
  Reduction in
                    Rate (gpm)'     Seepage (gpm)          Levels2      
  Lake Level ft)3
Lake         Expected Maximum  Expected Maximum   Expected Maximum

Little Sand    420        537        553       693      (0) 82    (0) 85
      0.95

Duck              3         3          8        12    (23) 33    (21) 25
      0.23

Skunk            44        75        115       130      (0) 0     (0) 0 
      0.99

Deep Hole        32        45         86       102     (18) 35   (24) 43
      0.40

2   Mitigation rates are equivalent to the mine-induced seepage when lakes
are at minimum levels.
2 Numbers in parentheses are percent time below minimum levels under natural
conditions.
3 Declines are from average lake levels.

Mitigation pumping would continue after mine closure as necessary. The groundwater
drawdown
would rebound to within one meter of pre-mining conditions within about six
years after mine
pumping was halted. Surface water impacts from the groundwater drawdown are
expected to be
insignificant at this time. With the cessation of the wastewater discharge,
water would no longer be
removed from the project area, and adequate quantities of mitigation water
would be available from
the glacial aquifer.


            ADDITIONAL PROJECT IMPACTS TO SURFACE WATERS, AQUATIC, AND
                                    TERRESTRIAL SYSTEMS

AIR EMISSIONS IMPACTS TO LAKES

The air deposition modeling results were used to assess the potential impacts
to surface waters as a
result of air emissions from the proposed mine site and tailings ponds. Impacts
to Little Sand, Duck,
and Deep Hole Lakes were evaluated. Because adverse water quality impacts
to other project area
lakes more remotely located from the mill and MWDF would not be expected,
an in-depth analysis of
them was not conducted. Air deposition rates for Skunk Lake would be similar
to the deposition rates
for Duck, Deep Hole and Little Sand Lakes. Deposition rates for Skunk Lake
were not evaluated
because it does not support a fish population, due to winter kills, or permanent
aquatic species
populations.

The analysis of water quality impacts from air emissions included the following
steps:

1.  Determination of a maximum aerial loading rate to each of the three lakes
based on deposition
    rates supplied by the air modeling results.



2. Calculation of changes that might be expected from background lake concentrations
as a resultI
    of the loading rates from air deposition sources.
                                            - 146 -



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