or airplane noise already present in the site area. Sources capable of emitting
instantaneous noise
would include warning horns prior to blasting and all clear signals after
blasting, blasting if large
boulders would be encountered during shaft sinking in the glacial materials,
backup alarms on
earthmoving equipment operating in reverse gear, and startup alarms for remotely-started
and
stopped equipment.

Most alarm devices would be high frequency in nature, thus there would be
considerable atmospheric
absorption. This would reduce annoyance to off-site, noise-sensitive locations.
Further, the alarm
systems on the trucks and other mobile construction equipment would be checked
to ensure that the
sound levels did not exceed the amount required for safety.

Traffic Noise - The Federal Highway Administration (FHWA) equation for predicting
noise at
distances of 50 feet or greater was used to estimate current and project-related
noise levels on State
Highway 55 north and south of the intersection with the proposed access road.
This equation is the
same as that used by the State of Wisconsin Department of Transportation.
Noise levels on STH 55
north of the mine/mill access road would increase 2 dB as a result of increased
traffic during
construction and 1 dB during operation. South of the access road on STH 55
noise levels would
increase 1 dB during both construction and operation. Increases of less than
3 dB would be barely
noticeable in the natural environment.
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ViUUbdrtI1on impacts - DidStLing WUUiU UoUcc  UUriuig Line cUoInlsULtLUci
onU UpUedrlUil piasest. DldLtin1g
should not have a large impact upon the environment during either phase.
The most noticeable
impacts are predicted for the construction blasting of the main and mine
ventilation shafts. These
impacts are predominately noise related rather than vibration related, and
would occur during prop
years 1 and 2 and years 8 and 9.

Production blasts fall into two categories: face blasts and production blasts.
Face blasts would oci
frequently, at the end of every shift but would be of small size. Face blasting
is associated with th
development of drifts, ore drawpoints, and mining of the upper portion of
the orebody during the
cut-and-fill operations. Production blasts would occur several times a week
on average but would
vary in size depending on the phase of stope development. During the early
phases of stope
development, the space available to accommodate blasted ore would be small.
As the stope slot
would be enlarged, however, progressively larger blasts with more explosives
would be used.

Shaft Sinking - Most of the excavation work in overburden soils would be
without the use of
explosives except where boulders are encountered and conventional excavation
equipment could no
loosen or break them.

The important blasting charge information related to seismic vibrations impacts
is the weight of
charge per delay, not the total charge weight. Each explosive firing for
the main shaft in bedrock
would require 352 pounds of dynamite. There would be 15 delays at each firing,
with an average of
pounds (maximum of 32 pounds) of explosives per delay period to provide adequate
shattering of
rock. The east exhaust raise would use the same general level of explosives
during bedrock
excavation. Blasting in the main shaft and east exhaust raise would be conducted
three times per:
hour period. The west exhaust raise would have explosives fired twice per
day. The total charge p
firing would be 500 pounds of dynamite. Fifteen separate delays per firing
would be used, with an
average of 33.5 pounds (maximum of 50.2 pounds) of explosive per delay period.
'Blasting for drifts
and ramps would be at the same level as for shafts.

Production Blasting in Stopes - Blasts in the stopes above the 450 foot level
and during the
cut-and-fill mining would require as much as 17,600 pounds of explosives
per firing, but with the u
of many delays. The charge in each delay would not exceed 550-660 pounds.

In the stopes below the 455 foot level, the usual blast would require 17,600
pounds overall, but six
delays, with 2,925 pounds per delay, would be used. Table 3-30 indicates
the charges per delay ant
resulting anticipated peak particle velocity.



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