kplonse No.                                    Response

185 As explained in the DEIS, tailings dust is the primary source of dust
that would contain
      minute amounts of heavy metals. For the most part, tailings dust would
not be present
      until after operations started and MWDF cell T-1 was in use. The key
to preventing
      significant dust impacts from the MWDF would be to prevent the tailings
surface from
      drying. It is unlikely that the tailings surface would dry due to the
fine grain of the
      tailings. Drying could occur if the-MWDF was taken out of service or
milling ceased. If
      that occurred, the Department would require sprinkling or other means
to continually wet
      the tailings mass surface. This level of detail would be covered in
the plan of operation.

186   Skunk Lake was omitted from the air impact analysis for the reasons
specified on DEIS
      page 139. The anticipated effects to Skunk Lake from predicted aerial
deposition would be
      similar to the effects on other nearby lakes shown in Table 3-20. Maximum
deposition
      rates would be extremely small, and would be unlikely to change background
levels and are,
      therefore, negligible. The combined impacts of mitigation impacts and
aerial deposition
      would be the same as the mitigation impacts.

187 It is not necessary to take into account "special populations which
may be at a higher risk
      due to the carcinogens in the dust." The unit risk factors used
in the air impact analysis to
      estimate potential cancer risk due to the project dust emissions take
into account the
      differences in sensitivity between people at various stages of their
lifetimes.

      The reference to the national cancer death rate is given to put the
previously predicted
      project-related risks into perspective. The worst case project risks
are negligible
      compared to normal cancer rates. On an individual basis, the risks
are considered small
      and, from a regulatory perspective, acceptable.

188   No field work to establish baseline metal deposition rates in the project
area was
      conducted because metal deposition due to the project was predicted
to be insignificant.
      The impact analysis for metals emissions on DEIS pages 155 to 157 confirmed
this. The
      predicted metal deposition rates on page 155 (Table 3-30) are far less
than the upper Great
      Lakes area background rates provided on DEIS page 77 (Table 2-20).

      No asbestiform background data are provided because no asbestiform
emissions are
      predicted. Please refer to response #184.

189   A noise management plan has been received from Exxon and is included
in the FEIS.
:
190   The noise levels in the area would increase as a result of project
implementation. Noise
      impacts are most detrimental to nesting and foraging wildlife. The
predicted noise levels
      at the closest bald eagle nest (currently on the north side of Rolling
Stone Lake) would not
      interfere with nesting or foraging. Osprey develop tenacious attachment
to nest sites and
      are known to tolerate high noise levels (nesting adjacent to major
highways and gravel
      crushing operations in the region). The pair of ospreys north of the
mill site is not
      expected to abandon the nest or produce fewer young due to noise impacts.
Maintenance
      of adequate no-impact zones around nest sites would help prevent disturbance.



      a ne uiscussion o0 vioration impacts nas been revised. The likelihood
ot simul
      is extremely remote with modem blasting practices.

192  The annual habitat requirements of Wisconsin endangered, threatened
and wa
     species in relation to mine impacts have been studied. Only a summary
of the
     major impacts was presented in the DEIS. The design and location of
the acc
     railroad spur, transmission lines, water pipelines, mitigation wells
and faciliti
     reclaim ponds and MWDF were chosen, after much discussion and study,
to m
     negative impacts to endangered, threatened and watch wildlife species
as we]
     habitats. Alternate routes and locations for mine facilities would have
great'
     these species and their habitats.



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