2016-02-03_PERMIT FILE - C1981038 ‎(2)‎

• Permit No: C1981038
• IBM Index Class Name: Permit File
• Doc Date: 2/3/2016
• Section_Exhibit Name: Volume 1 2.04 Environmental Resources
• Media Type: D
• Archive: No

32.04 APPLICATION FOR PERMIT FOR SIIRFACE OR UNDERGROIIND MINING ACTfVITIES --
• MINIMUM REQUIREMENTS FOR INFORMATION ON ENVIRONMENTAL RESOURCES.
2.04.8 Climatological Information.
(1) Climatic Characteristics of the North Fork Valley (Cont'd,)
(b) and (c) (Cont'd.)
intensity of the illumination -- sun, moon, artificial
light; b) the refraction, scattering, and absorption of
the light by the atmosphere and its contaminants; (c)
the reflection, absorption and scattering of the light
by the target objects and, perhaps most importantly; d)
the phycophysical response of the human eye-brain sys-
tem to the resulting light, contrast and color distri-
bution.
An important criteria in visibility is contrast. The
detection of contrast between an object and its back-
ground or surroundings is fundamental to the evaluation
of visibility. A candle in a brightly lit room is al-
most unnoticeable, however, if the room is dim or dark,
the light of the candle is quite bright. Trees (in
full sunlight) appear dark against the sky, but appear
bright if viewed against the shadowed valley floor from
• a mountain ridge. As a contrast between the target and
background is reduced (by increased pollution, for ex-
ample), the target becomes less distinct. The smallest
perceptible change is a function of the distance and
the extinction coefficient due to the attenuation by
contaminants according to the equation:
-dI = RextIdx
where: -dI = the decrease in intensity
Bext the extinction coefficient
I = the original intensity of light
dx the path length between target and
observer
The reduced brightness, therefore, is not usually the
primary factor limiting an object's visibility. If it
were, the stars would be visible in daylight since
their light traverses the same atmosphere day and
night. In addition to the light originating at the
target (a distant light at night), the observer re-
ceives extraneous light scattered into the line of
sight from aerosol (wet and dry haze). It is this "air
• Revised 08/01/84
Revised 10/01/87
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